From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <SRS0=klx1=BW=lists.ozlabs.org=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@kernel.org>
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=-12.8 required=3.0 tests=BAYES_00,DKIM_INVALID,
	DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,
	SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham
	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 467FEC433E0
	for <linuxppc-dev@archiver.kernel.org>; Wed, 12 Aug 2020 06:36:49 +0000 (UTC)
Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2])
	(using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits))
	(No client certificate requested)
	by mail.kernel.org (Postfix) with ESMTPS id B0A0120768
	for <linuxppc-dev@archiver.kernel.org>; Wed, 12 Aug 2020 06:36:48 +0000 (UTC)
Authentication-Results: mail.kernel.org;
	dkim=fail reason="signature verification failed" (2048-bit key) header.d=ibm.com header.i=@ibm.com header.b="GrgbhBIX"
DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B0A0120768
Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.ibm.com
Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org
Received: from bilbo.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3])
	by lists.ozlabs.org (Postfix) with ESMTP id 4BRKjp1wnmzDqVp
	for <linuxppc-dev@archiver.kernel.org>; Wed, 12 Aug 2020 16:36:46 +1000 (AEST)
Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized)
 smtp.mailfrom=linux.ibm.com (client-ip=148.163.158.5;
 helo=mx0a-001b2d01.pphosted.com; envelope-from=aneesh.kumar@linux.ibm.com;
 receiver=<UNKNOWN>)
Authentication-Results: lists.ozlabs.org;
 dmarc=pass (p=none dis=none) header.from=linux.ibm.com
Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key;
 unprotected) header.d=ibm.com header.i=@ibm.com header.a=rsa-sha256
 header.s=pp1 header.b=GrgbhBIX; dkim-atps=neutral
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 4BRKgF0HwKzDqQ9
 for <linuxppc-dev@lists.ozlabs.org>; Wed, 12 Aug 2020 16:34:32 +1000 (AEST)
Received: from pps.filterd (m0098419.ppops.net [127.0.0.1])
 by mx0b-001b2d01.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id
 07C6W2gi103009; Wed, 12 Aug 2020 02:34:20 -0400
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com;
 h=from : to : cc : subject
 : date : message-id : mime-version : content-transfer-encoding; s=pp1;
 bh=LVwTeyKe/+eadJkxhdcPDPb/XZX3HzejRljrDbr75SI=;
 b=GrgbhBIXQXEVCTLaUj0UAfJEf4ckUn5XbScEB3A3lCJP+4rIpgZJ69D6KQTzRwW/5TA6
 Iux4HpWFKnzBKx2GfKJC2jsDhzckE6qMqxnLwYkLC4macRVR2qrFjUC/fDMzRFyzcR/D
 b5PylWXH27ffAA5JAuyc1k6+uGgOaEJ6jln6RsQmsIU279nxrtAcQ+N/FmprlJz8omgz
 QlBw9U79sI9a3z6H8CDvk87o3R6GUsV/1Tn/M0guSyFoKlrWgqGU0T7FpD8f2P1cSDtN
 U2FRu2SbWtqOKPuE3wU/2i5bmIO0t8pMZ2wdXa/GlNXDNX9fmn5lFiVaYdQztzTlLIh4 og== 
Received: from ppma02wdc.us.ibm.com (aa.5b.37a9.ip4.static.sl-reverse.com
 [169.55.91.170])
 by mx0b-001b2d01.pphosted.com with ESMTP id 32uqp3s8r5-1
 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT);
 Wed, 12 Aug 2020 02:34:20 -0400
Received: from pps.filterd (ppma02wdc.us.ibm.com [127.0.0.1])
 by ppma02wdc.us.ibm.com (8.16.0.42/8.16.0.42) with SMTP id 07C6FtW7023219;
 Wed, 12 Aug 2020 06:34:20 GMT
Received: from b03cxnp07029.gho.boulder.ibm.com
 (b03cxnp07029.gho.boulder.ibm.com [9.17.130.16])
 by ppma02wdc.us.ibm.com with ESMTP id 32skp97cbu-1
 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT);
 Wed, 12 Aug 2020 06:34:20 +0000
Received: from b03ledav002.gho.boulder.ibm.com
 (b03ledav002.gho.boulder.ibm.com [9.17.130.233])
 by b03cxnp07029.gho.boulder.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id
 07C6YJKi45875632
 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK);
 Wed, 12 Aug 2020 06:34:19 GMT
Received: from b03ledav002.gho.boulder.ibm.com (unknown [127.0.0.1])
 by IMSVA (Postfix) with ESMTP id 5447113604F;
 Wed, 12 Aug 2020 06:34:19 +0000 (GMT)
Received: from b03ledav002.gho.boulder.ibm.com (unknown [127.0.0.1])
 by IMSVA (Postfix) with ESMTP id 09459136055;
 Wed, 12 Aug 2020 06:34:16 +0000 (GMT)
Received: from skywalker.ibmuc.com (unknown [9.85.71.109])
 by b03ledav002.gho.boulder.ibm.com (Postfix) with ESMTP;
 Wed, 12 Aug 2020 06:34:16 +0000 (GMT)
From: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
To: linux-mm@kvack.org, akpm@linux-foundation.org
Subject: [PATCH 01/16] powerpc/mm: Add DEBUG_VM WARN for pmd_clear
Date: Wed, 12 Aug 2020 12:03:43 +0530
Message-Id: <20200812063358.369514-1-aneesh.kumar@linux.ibm.com>
X-Mailer: git-send-email 2.26.2
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
X-TM-AS-GCONF: 00
X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.235, 18.0.687
 definitions=2020-08-11_19:2020-08-11,
 2020-08-11 signatures=0
X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0
 lowpriorityscore=0
 bulkscore=0 spamscore=0 priorityscore=1501 mlxscore=0 impostorscore=0
 mlxlogscore=999 malwarescore=0 suspectscore=0 adultscore=0 phishscore=0
 clxscore=1015 classifier=spam adjust=0 reason=mlx scancount=1
 engine=8.12.0-2006250000 definitions=main-2008120044
X-BeenThere: linuxppc-dev@lists.ozlabs.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: Linux on PowerPC Developers Mail List <linuxppc-dev.lists.ozlabs.org>
List-Unsubscribe: <https://lists.ozlabs.org/options/linuxppc-dev>,
 <mailto:linuxppc-dev-request@lists.ozlabs.org?subject=unsubscribe>
List-Archive: <http://lists.ozlabs.org/pipermail/linuxppc-dev/>
List-Post: <mailto:linuxppc-dev@lists.ozlabs.org>
List-Help: <mailto:linuxppc-dev-request@lists.ozlabs.org?subject=help>
List-Subscribe: <https://lists.ozlabs.org/listinfo/linuxppc-dev>,
 <mailto:linuxppc-dev-request@lists.ozlabs.org?subject=subscribe>
Cc: linuxppc-dev@lists.ozlabs.org,
 "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>,
 Anshuman Khandual <anshuman.khandual@arm.com>
Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org
Sender: "Linuxppc-dev"
 <linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org>

With the hash page table, the kernel should not use pmd_clear for clearing
huge pte entries. Add a DEBUG_VM WARN to catch the wrong usage.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
---
 arch/powerpc/include/asm/book3s/64/pgtable.h | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h
index 6de56c3b33c4..079211968987 100644
--- a/arch/powerpc/include/asm/book3s/64/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
@@ -868,6 +868,13 @@ static inline bool pte_ci(pte_t pte)
 
 static inline void pmd_clear(pmd_t *pmdp)
 {
+	if (IS_ENABLED(CONFIG_DEBUG_VM) && !radix_enabled()) {
+		/*
+		 * Don't use this if we can possibly have a hash page table
+		 * entry mapping this.
+		 */
+		WARN_ON((pmd_val(*pmdp) & (H_PAGE_HASHPTE | _PAGE_PTE)) == (H_PAGE_HASHPTE | _PAGE_PTE));
+	}
 	*pmdp = __pmd(0);
 }
 
@@ -916,6 +923,13 @@ static inline int pmd_bad(pmd_t pmd)
 
 static inline void pud_clear(pud_t *pudp)
 {
+	if (IS_ENABLED(CONFIG_DEBUG_VM) && !radix_enabled()) {
+		/*
+		 * Don't use this if we can possibly have a hash page table
+		 * entry mapping this.
+		 */
+		WARN_ON((pud_val(*pudp) & (H_PAGE_HASHPTE | _PAGE_PTE)) == (H_PAGE_HASHPTE | _PAGE_PTE));
+	}
 	*pudp = __pud(0);
 }
 
-- 
2.26.2