Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
IronPort-SDR: 9WYyv5mmoBPB8PiA0pCUB0JmhI6ETvK6pzZFmC0CJ5vEfPuo82TDr/Cbi5DL8zkyWreGJ/TBmu
 FYCNf8EJZbd1yOWH8pw2oJiu+cv82v+Xu0KSbY1Kc/xw5xDyK1EXFfuZtO3kxmtGg9chf/U+m0
 rIY5jVg6R492Fi2qeh4oyHjGqhz3035xZcRrsMEAwgrlzTJb/r3XQ4U4phlGO/wcQ+FBZZ3lrm
 XX2hczeAV9NTluBMGXsryont4AM7cejWN/ZL4owzyGOJj0LHeqXOW58s7t4nPcCv/agv8zTSU5
 nUg=
From:   Anup Patel <anup.patel@wdc.com>
To:     Palmer Dabbelt <palmer@dabbelt.com>,
        Palmer Dabbelt <palmerdabbelt@google.com>,
        Paul Walmsley <paul.walmsley@sifive.com>,
        Albert Ou <aou@eecs.berkeley.edu>
Cc:     Atish Patra <atish.patra@wdc.com>,
        Alistair Francis <Alistair.Francis@wdc.com>,
        Anup Patel <anup@brainfault.org>,
        linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
        Anup Patel <anup.patel@wdc.com>
Subject: [PATCH] RISC-V: Use non-PGD mappings for early DTB access
Date:   Wed,  4 Nov 2020 12:07:13 +0530
Message-Id: <20201104063713.3039035-1-anup.patel@wdc.com>
Content-Transfer-Encoding: 8bit
Content-Type: text/plain
MIME-Version: 1.0
X-MS-Exchange-MessageSentRepresentingType: 1
Received: from wdc.com (122.171.38.184) by MAXPR01CA0094.INDPRD01.PROD.OUTLOOK.COM (2603:1096:a00:49::36) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.3499.19 via Frontend Transport; Wed, 4 Nov 2020 06:37:33 +0000
X-MS-PublicTrafficType: Email
X-MS-Office365-Filtering-HT: Tenant
X-MS-Office365-Filtering-Correlation-Id: c02ac2d9-df2e-4f05-69d7-08d8808c1e77
X-MS-TrafficTypeDiagnostic: DM5PR04MB0685:
X-MS-Exchange-Transport-Forked: True
X-Microsoft-Antispam-PRVS: <DM5PR04MB0685A8345E43E217195C385C8DEF0@DM5PR04MB0685.namprd04.prod.outlook.com>
WDCIPOUTBOUND: EOP-TRUE
X-MS-Oob-TLC-OOBClassifiers: OLM:3173;
X-MS-Exchange-SenderADCheck: 1
X-Microsoft-Antispam: BCL:0;
X-Microsoft-Antispam-Message-Info: sLjTNZ8ZbbNXR5/uLckDxwcYXfGC2sr6WLWhFJHODcBtm4mPAAG3QJ6XYb9Yu2e+gHFEK6debbpWpwTFsPuA1BgrKbh7aiqAPWO4uaSLLSwukDgGzc8DDuxkT6lv4BHoEsln2aPFb+Rr5VsSmH3q5eGRwV626s5bzgzdjKVkeR29A8H9uvbCjCdqbVTeBeX3SibrgKNmYKn9JBq2GvLTQ0YC+dPHP8eqqRognAhj1Lx6Uhjp5KFGF+NuZbAXOaU2BarvVp9f+VCuHMt/+nG0wGOyMlyMy9mw28X0NB9neZ1v0sZeD/LwYiuNnHNOeJjKaXEVhLSzy7rpKuCnkyf3SA==
X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:DM6PR04MB6201.namprd04.prod.outlook.com;PTR:;CAT:NONE;SFS:(4636009)(39860400002)(346002)(396003)(366004)(136003)(376002)(16526019)(110136005)(86362001)(66476007)(66556008)(6666004)(186003)(52116002)(36756003)(55016002)(8676002)(54906003)(7696005)(1076003)(4326008)(2906002)(8886007)(66946007)(478600001)(44832011)(83380400001)(5660300002)(2616005)(26005)(8936002)(316002)(956004);DIR:OUT;SFP:1102;
X-MS-Exchange-AntiSpam-MessageData: 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
X-OriginatorOrg: wdc.com
X-MS-Exchange-CrossTenant-Network-Message-Id: c02ac2d9-df2e-4f05-69d7-08d8808c1e77
X-MS-Exchange-CrossTenant-AuthSource: DM6PR04MB6201.namprd04.prod.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 04 Nov 2020 06:37:36.9813
 (UTC)
X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted
X-MS-Exchange-CrossTenant-Id: b61c8803-16f3-4c35-9b17-6f65f441df86
X-MS-Exchange-CrossTenant-MailboxType: HOSTED
X-MS-Exchange-CrossTenant-UserPrincipalName: /wBgFaw4nKSq7fVTCrdZK5dJkIn87nitPyZyLMAllyb90B1zAgkjQdyUz6eR6g2eC9RRQjafsIwTXwOGfGcY0g==
X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM5PR04MB0685
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

Currently, we use PGD mappings for early DTB mapping in early_pgd
but this breaks Linux kernel on SiFive Unleashed because on SiFive
Unleashed PMP checks don't work correctly for PGD mappings.

To fix early DTB mappings on SiFive Unleashed, we use non-PGD
mappings (i.e. PMD) for early DTB access.

Fixes: 8f3a2b4a96dc ("RISC-V: Move DT mapping outof fixmap")
Signed-off-by: Anup Patel <anup.patel@wdc.com>
---
 arch/riscv/mm/init.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
index ea933b789a88..0d13d0c36a7d 100644
--- a/arch/riscv/mm/init.c
+++ b/arch/riscv/mm/init.c
@@ -297,6 +297,7 @@ pmd_t fixmap_pmd[PTRS_PER_PMD] __page_aligned_bss;
 #define NUM_EARLY_PMDS		(1UL + MAX_EARLY_MAPPING_SIZE / PGDIR_SIZE)
 #endif
 pmd_t early_pmd[PTRS_PER_PMD * NUM_EARLY_PMDS] __initdata __aligned(PAGE_SIZE);
+pmd_t early_dtb_pmd[PTRS_PER_PMD] __initdata __aligned(PAGE_SIZE);
 
 static pmd_t *__init get_pmd_virt_early(phys_addr_t pa)
 {
@@ -494,6 +495,18 @@ asmlinkage void __init setup_vm(uintptr_t dtb_pa)
 				   load_pa + (va - PAGE_OFFSET),
 				   map_size, PAGE_KERNEL_EXEC);
 
+#ifndef __PAGETABLE_PMD_FOLDED
+	/* Setup early PMD for DTB */
+	create_pgd_mapping(early_pg_dir, DTB_EARLY_BASE_VA,
+			   (uintptr_t)early_dtb_pmd, PGDIR_SIZE, PAGE_TABLE);
+	/* Create two consecutive PMD mappings for FDT early scan */
+	pa = dtb_pa & ~(PMD_SIZE - 1);
+	create_pmd_mapping(early_dtb_pmd, DTB_EARLY_BASE_VA,
+			   pa, PMD_SIZE, PAGE_KERNEL);
+	create_pmd_mapping(early_dtb_pmd, DTB_EARLY_BASE_VA + PMD_SIZE,
+			   pa + PMD_SIZE, PMD_SIZE, PAGE_KERNEL);
+	dtb_early_va = (void *)DTB_EARLY_BASE_VA + (dtb_pa & (PMD_SIZE - 1));
+#else
 	/* Create two consecutive PGD mappings for FDT early scan */
 	pa = dtb_pa & ~(PGDIR_SIZE - 1);
 	create_pgd_mapping(early_pg_dir, DTB_EARLY_BASE_VA,
@@ -501,6 +514,7 @@ asmlinkage void __init setup_vm(uintptr_t dtb_pa)
 	create_pgd_mapping(early_pg_dir, DTB_EARLY_BASE_VA + PGDIR_SIZE,
 			   pa + PGDIR_SIZE, PGDIR_SIZE, PAGE_KERNEL);
 	dtb_early_va = (void *)DTB_EARLY_BASE_VA + (dtb_pa & (PGDIR_SIZE - 1));
+#endif
 	dtb_early_pa = dtb_pa;
 
 	/*
-- 
2.25.1