linux-kernel - [PATCH] ARM: mm: set readonly for MT_MEMORY_RO with ARM

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Message-ID: <20220913133022.145977-1-wangkefeng.wang@huawei.com>
Date:   Tue, 13 Sep 2022 21:30:22 +0800
From:   Kefeng Wang <wangkefeng.wang@...wei.com>
To:     Russell King <linux@...linux.org.uk>,
        <linux-arm-kernel@...ts.infradead.org>
CC:     Ard Biesheuvel <ardb@...nel.org>, <linux-kernel@...r.kernel.org>,
        Zhen Lei <thunder.leizhen@...wei.com>,
        Kefeng Wang <wangkefeng.wang@...wei.com>
Subject: [PATCH] ARM: mm: set readonly for MT_MEMORY_RO with ARM_LPAE

MT_MEMORY_RO is introduced by commit 598f0a99fa8a ("ARM: 9210/1:
Mark the FDT_FIXED sections as shareable"), which is a readonly
memory type for FDT area, but there are some different between
ARM_LPAE and non-ARM_LPAE, we need to setup PMD_SECT_AP2 and
L_PMD_SECT_RDONLY for MT_MEMORY_RO when ARM_LAPE enabled.

non-ARM_LPAE	0xff800000-0xffa00000           2M PGD KERNEL      ro NX SHD
ARM_LPAE	0xff800000-0xffc00000           4M PMD RW NX SHD
ARM_LPAE+fix	0xff800000-0xffc00000           4M PMD ro NX SHD

Fixes: 598f0a99fa8a ("ARM: 9210/1: Mark the FDT_FIXED sections as shareable")
Signed-off-by: Kefeng Wang <wangkefeng.wang@...wei.com>
---
 arch/arm/mm/mmu.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
index a49f0b9c0f75..b8d273651003 100644
--- a/arch/arm/mm/mmu.c
+++ b/arch/arm/mm/mmu.c
@@ -300,7 +300,11 @@ static struct mem_type mem_types[] __ro_after_init = {
 		.prot_pte  = L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY |
 			     L_PTE_XN | L_PTE_RDONLY,
 		.prot_l1   = PMD_TYPE_TABLE,
+#ifndef CONFIG_ARM_LPAE
 		.prot_sect = PMD_TYPE_SECT,
+#else
+		.prot_sect = PMD_TYPE_SECT | L_PMD_SECT_RDONLY | PMD_SECT_AP2,
+#endif
 		.domain    = DOMAIN_KERNEL,
 	},
 	[MT_ROM] = {
-- 
2.35.3