Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
From:   Chuanhua Han <hanchuanhua@oppo.com>
To:     paul.walmsley@sifive.com, palmer@dabbelt.com, aou@eecs.berkeley.edu
Cc:     alexandre.ghiti@canonical.com, jszhang@kernel.org,
        mhiramat@kernel.org, akpm@linux-foundation.org,
        zhengqi.arch@bytedance.com, ebiederm@xmission.com,
        liushixin2@huawei.com, linux-riscv@lists.infradead.org,
        linux-kernel@vger.kernel.org, hanchuanhua <hanchuanhua@oppo.com>
Subject: [PATCH v3] riscv: mm: Remove the copy operation of pmd
Date:   Thu, 31 Mar 2022 19:29:06 -0700
Message-Id: <20220401022906.97710-1-hanchuanhua@oppo.com>
Content-Transfer-Encoding: 8bit
Content-Type: text/plain
MIME-Version: 1.0
X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1
X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?It2KJXXParcAiRVAc7vvM07gG/HroFki3iJTa11RxwN+zMvxAi1PevjwEhI3?=
 =?us-ascii?Q?bXeqO/GovWB3P1CW7n/G7MWN0ecHJ/ump3oq/srjFZ0Y3tuonJBqR3RJjMct?=
 =?us-ascii?Q?CXqETIetNlTWxZmng9XHSzimCP+3nF+qrqIvZDb6KAR381P2ZViV0cYxsVty?=
 =?us-ascii?Q?ytOl8I2i60WAOJPieTVDEpELnpLWbnlm+WtVzmfVkKfducsXWXnrho4KG2If?=
 =?us-ascii?Q?PCbODrdW642Rd8uwrhLxQj+K/+h9cLxp6VIgNbExfS7Cuk+6FERZvZGW1kDF?=
 =?us-ascii?Q?3lQXwS0p52pQoAjP+CP/qmOZrMq+WMlqFi4snh46RLF2W9pKZ+QZOv5X77gq?=
 =?us-ascii?Q?JqWXEumvuaSoVczmaMc79fI0LNGWtUDMOe14FlGA4BF6zcuF+i4lAX0pUVVm?=
 =?us-ascii?Q?oq31eEFwMRf35CnrisWQWz1pSqkxe1gNSYzl7nWFnNBJ7V0/nSx35UiqXevq?=
 =?us-ascii?Q?Bs3klls1tc5s27WqN2jCL+5fY4LuPxZPRvnTkes9sMxeQ5kCa7sqfXbzKSoe?=
 =?us-ascii?Q?LTGO8tiWv5888FKLJ5RoS5spYVS4Oe532xxeXTlAgMIAGiEVBWKrJgIH1vHs?=
 =?us-ascii?Q?5yy4WAaVLzn4e0pRcFuvqkWIWTW+i5UQWtiOblAPyvFfaEQszOlpA5H1Y/nO?=
 =?us-ascii?Q?orgJZq0cRRIB+oi9Exro+78CxCIf5Ixbl+Te3OX2OUSArj+A/28czt74xV4k?=
 =?us-ascii?Q?4Q/VksiJZlGLTpXZdZDRMOpwbsKc+UhqWKLwKRUWQmPzhWICW3BVLw8oBMDa?=
 =?us-ascii?Q?vyYIlLtUFWy3Of8n7Q4AHqDB60F3AyDUKUwwHkV16AUKL9lxUOeTBYtSPKog?=
 =?us-ascii?Q?P5qufMC6WhH9xzzNduwH94J9/mJlMJREMRwD4obk5cz9pZFYYJV7U75Nn8uP?=
 =?us-ascii?Q?JS199KgpB3gWUlqgwb33Av4dDsS9YrXcnMzaY25/Vryn7fkUVzVBK4CYdAb1?=
 =?us-ascii?Q?cnbvDyyb2vpfzyZAEP65JAlyoXrQmqJXCcZN/hrTJxLOYaS9oTYUKnWl6Tnh?=
 =?us-ascii?Q?azeec4ozLvfkuIzbN2fyjsu/7Gh3++/mnTaPBvWJfjrsz9lDs8E01xP/U+hJ?=
 =?us-ascii?Q?Ps8pswgAlEzyjULA9aC+IUD2vzgAbNlitRnuuz0DrfV3ASJJVQlKwNSHaY3v?=
 =?us-ascii?Q?5g1Doua3kM5F1IbRFEd5/1VF0txG80BSDBD0FlL/UfyEHDlfBWF5kf4BOi7v?=
 =?us-ascii?Q?+RJdRSH7RqP5bwq5av1JACF3EKzvLpPDmw0NGM0WtcJF5bKyiHJEshVOinSX?=
 =?us-ascii?Q?moDQ9PztfteJcIoWh/1iJ3oT72UtIoxyeuBEB3uclbeA5SI6sGTvFa9RGnoC?=
 =?us-ascii?Q?6htMNg+VRX+Mea/EjZz0H4CJyLFSr1ZGzQgnAqAi4flmHBt7IuMxXx42JRRA?=
 =?us-ascii?Q?9fAd31jtaEmAK0tGJcHuZ1u8ce2/NsHIdj1XvP4H7MGb/1NT4mK3PO4R6pJ+?=
 =?us-ascii?Q?F6N/xk0F52Pu9aq3xuUgs3n5a3w1RfpEtl0gUzmhKy1BcQlcclfsCDvShzRZ?=
 =?us-ascii?Q?AN9nIXz8u6oGOCczSw0R3py9WtG82NWeuxNA0hZfGpO4aQEkE2b6nuBFiHxQ?=
 =?us-ascii?Q?IHwoorYnXSQkYcactw8p2mk1/pYO6itQ/nE5ZRZ72zAT0nuHmaaiMruquF5W?=
 =?us-ascii?Q?j4ysCEPnxNeWKiyuFKDJwcNAEU0wpalkVrh8Hbw6B95ROgCls3uhVKCLfT4y?=
 =?us-ascii?Q?fy25kNnDez+dURuCoQWdiZ3vVf8WP2PYusbpvIs4Q5COrq9uuFwlG1t2AZz6?=
 =?us-ascii?Q?seRRdfMHD8BPWwzjWgEzFI/D3c15zko=3D?=
X-OriginatorOrg: oppo.com
X-MS-Exchange-CrossTenant-Network-Message-Id: 045f2653-e6e8-456a-bb12-08da13876c9e
X-MS-Exchange-CrossTenant-AuthSource: SG2PR02MB5379.apcprd02.prod.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 01 Apr 2022 02:29:19.1763
 (UTC)
X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted
X-MS-Exchange-CrossTenant-Id: f1905eb1-c353-41c5-9516-62b4a54b5ee6
X-MS-Exchange-CrossTenant-MailboxType: HOSTED
X-MS-Exchange-CrossTenant-UserPrincipalName: 6Rs3GjvFimtVVDzsEd+WCqHBdsGoK8swR7Bh6qUA5o2qjUQcIGegRIRxBf3nzPN3WE55+DmGn0yxLA/9ARJu2w==
X-MS-Exchange-Transport-CrossTenantHeadersStamped: TY0PR02MB5873
X-Spam-Status: No, score=-1.7 required=5.0 tests=BAYES_00,DKIM_INVALID,
        DKIM_SIGNED,RCVD_IN_DNSWL_NONE,RCVD_IN_MSPIKE_H2,SPF_HELO_PASS,
        SPF_PASS,T_SCC_BODY_TEXT_LINE autolearn=no autolearn_force=no
        version=3.4.6
X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on
        lindbergh.monkeyblade.net
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

From: hanchuanhua <hanchuanhua@oppo.com>

Since all processes share the kernel address space,
we only need to copy pgd in case of a vmalloc page
fault exception, the other levels of page tables are
shared, so the operation of copying pmd is unnecessary.

Signed-off-by: Chuanhua Han <hanchuanhua@oppo.com>
---
Changes in v3:
  -Change the real name of signed-off-by.

Changes in v2:
  -Delete incorrect default signatures.

 arch/riscv/mm/fault.c | 10 +++-------
 1 file changed, 3 insertions(+), 7 deletions(-)

diff --git a/arch/riscv/mm/fault.c b/arch/riscv/mm/fault.c
index 4e9efbe46d5f..40694f0cab9e 100644
--- a/arch/riscv/mm/fault.c
+++ b/arch/riscv/mm/fault.c
@@ -102,9 +102,9 @@ static inline void bad_area(struct pt_regs *regs, struct mm_struct *mm, int code
 static inline void vmalloc_fault(struct pt_regs *regs, int code, unsigned long addr)
 {
 	pgd_t *pgd, *pgd_k;
-	pud_t *pud, *pud_k;
-	p4d_t *p4d, *p4d_k;
-	pmd_t *pmd, *pmd_k;
+	pud_t *pud_k;
+	p4d_t *p4d_k;
+	pmd_t *pmd_k;
 	pte_t *pte_k;
 	int index;
 	unsigned long pfn;
@@ -132,14 +132,12 @@ static inline void vmalloc_fault(struct pt_regs *regs, int code, unsigned long a
 	}
 	set_pgd(pgd, *pgd_k);
 
-	p4d = p4d_offset(pgd, addr);
 	p4d_k = p4d_offset(pgd_k, addr);
 	if (!p4d_present(*p4d_k)) {
 		no_context(regs, addr);
 		return;
 	}
 
-	pud = pud_offset(p4d, addr);
 	pud_k = pud_offset(p4d_k, addr);
 	if (!pud_present(*pud_k)) {
 		no_context(regs, addr);
@@ -150,13 +148,11 @@ static inline void vmalloc_fault(struct pt_regs *regs, int code, unsigned long a
 	 * Since the vmalloc area is global, it is unnecessary
 	 * to copy individual PTEs
 	 */
-	pmd = pmd_offset(pud, addr);
 	pmd_k = pmd_offset(pud_k, addr);
 	if (!pmd_present(*pmd_k)) {
 		no_context(regs, addr);
 		return;
 	}
-	set_pmd(pmd, *pmd_k);
 
 	/*
 	 * Make sure the actual PTE exists as well to
-- 
2.25.1