arm64: add PTE_WRITE to PROT_SECT_NORMAL

With PIE enabled, PROT_SECT_NORMAL would map onto PAGE_KERNEL_RO.
Add PTE_WRITE so that this maps onto PAGE_KERNEL, so that it is writable.

Without PIE, this should enable DBM for PROT_SECT_NORMAL. However PTE_RDONLY
is already cleared, so the DBM mechanism is not used, and it is always writable,
so this is functionally equivalent.

Signed-off-by: Joey Gouly <joey.gouly@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20230606145859.697944-13-joey.gouly@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

diff --git a/arch/arm64/include/asm/pgtable-prot.h b/arch/arm64/include/asm/pgtable-prot.h
index 9b165117a454595a3b232c6857efb13619c54286..d26d0b427c0a9ad9ba4b5ee1900b48f73ffbdd84 100644 (file)
--- a/arch/arm64/include/asm/pgtable-prot.h
+++ b/arch/arm64/include/asm/pgtable-prot.h
@@ -60,7 +60,7 @@ extern bool arm64_use_ng_mappings;
 #define PROT_NORMAL_TAGGED     (PROT_DEFAULT | PTE_PXN | PTE_UXN | PTE_WRITE | PTE_ATTRINDX(MT_NORMAL_TAGGED))
 
 #define PROT_SECT_DEVICE_nGnRE (PROT_SECT_DEFAULT | PMD_SECT_PXN | PMD_SECT_UXN | PMD_ATTRINDX(MT_DEVICE_nGnRE))
-#define PROT_SECT_NORMAL       (PROT_SECT_DEFAULT | PMD_SECT_PXN | PMD_SECT_UXN | PMD_ATTRINDX(MT_NORMAL))
+#define PROT_SECT_NORMAL       (PROT_SECT_DEFAULT | PMD_SECT_PXN | PMD_SECT_UXN | PTE_WRITE | PMD_ATTRINDX(MT_NORMAL))
 #define PROT_SECT_NORMAL_EXEC  (PROT_SECT_DEFAULT | PMD_SECT_UXN | PMD_ATTRINDX(MT_NORMAL))
 
 #define _PAGE_DEFAULT          (_PROT_DEFAULT | PTE_ATTRINDX(MT_NORMAL))