From: Will Deacon <will@kernel.org>
Date: Fri, 20 Nov 2020 13:57:48 +0000
Subject: arm64: pgtable: Ensure dirty bit is preserved across pte_wrprotect()
Git-commit: ff1712f953e27f0b0718762ec17d0adb15c9fd0b
Patch-mainline: v5.10-rc6
References: bsc#1180130
With hardware dirty bit management, calling pte_wrprotect() on a writable,
dirty PTE will lose the dirty state and return a read-only, clean entry.
Move the logic from ptep_set_wrprotect() into pte_wrprotect() to ensure that
the dirty bit is preserved for writable entries, as this is required for
soft-dirty bit management if we enable it in the future.
Cc: <stable@vger.kernel.org>
Fixes: 2f4b829c625e ("arm64: Add support for hardware updates of the access and dirty pte bits")
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20201120143557.6715-3-will@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Mian Yousaf Kaukab <ykaukab@suse.de>
---
arch/arm64/include/asm/pgtable.h | 27 ++++++++++++++-------------
1 file changed, 14 insertions(+), 13 deletions(-)
diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index 326c34677e86..5628289b9d5e 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -165,13 +165,6 @@ static inline pmd_t set_pmd_bit(pmd_t pmd, pgprot_t prot)
return pte;
}
-static inline pte_t pte_wrprotect(pte_t pte)
-{
- pte = clear_pte_bit(pte, __pgprot(PTE_WRITE));
- pte = set_pte_bit(pte, __pgprot(PTE_RDONLY));
- return pte;
-}
-
static inline pte_t pte_mkwrite(pte_t pte)
{
pte = set_pte_bit(pte, __pgprot(PTE_WRITE));
@@ -197,6 +190,20 @@ static inline pte_t pte_mkdirty(pte_t pte)
return pte;
}
+static inline pte_t pte_wrprotect(pte_t pte)
+{
+ /*
+ * If hardware-dirty (PTE_WRITE/DBM bit set and PTE_RDONLY
+ * clear), set the PTE_DIRTY bit.
+ */
+ if (pte_hw_dirty(pte))
+ pte = pte_mkdirty(pte);
+
+ pte = clear_pte_bit(pte, __pgprot(PTE_WRITE));
+ pte = set_pte_bit(pte, __pgprot(PTE_RDONLY));
+ return pte;
+}
+
static inline pte_t pte_mkold(pte_t pte)
{
return clear_pte_bit(pte, __pgprot(PTE_AF));
@@ -846,12 +853,6 @@ static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long addres
pte = READ_ONCE(*ptep);
do {
old_pte = pte;
- /*
- * If hardware-dirty (PTE_WRITE/DBM bit set and PTE_RDONLY
- * clear), set the PTE_DIRTY bit.
- */
- if (pte_hw_dirty(pte))
- pte = pte_mkdirty(pte);
pte = pte_wrprotect(pte);
pte_val(pte) = cmpxchg_relaxed(&pte_val(*ptep),
pte_val(old_pte), pte_val(pte));
--
2.26.2