LoongArch: Set _PAGE_DIRTY only if _PAGE_MODIFIED is set in {pmd,pte}_mkwrite()

Set _PAGE_DIRTY only if _PAGE_MODIFIED is set in {pmd,pte}_mkwrite().
Otherwise, _PAGE_DIRTY silences the TLB modify exception and make us
have no chance to mark a pmd/pte dirty (_PAGE_MODIFIED) for software.

Reviewed-by: Guo Ren <guoren@kernel.org>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

diff --git a/arch/loongarch/include/asm/pgtable.h b/arch/loongarch/include/asm/pgtable.h
index debbe11..aa0e0e0 100644 (file)
--- a/arch/loongarch/include/asm/pgtable.h
+++ b/arch/loongarch/include/asm/pgtable.h
@@ -357,7 +357,9 @@ static inline pte_t pte_mkdirty(pte_t pte)
 
 static inline pte_t pte_mkwrite(pte_t pte)
 {
-       pte_val(pte) |= (_PAGE_WRITE | _PAGE_DIRTY);
+       pte_val(pte) |= _PAGE_WRITE;
+       if (pte_val(pte) & _PAGE_MODIFIED)
+               pte_val(pte) |= _PAGE_DIRTY;
        return pte;
 }
 
@@ -457,7 +459,9 @@ static inline int pmd_write(pmd_t pmd)
 
 static inline pmd_t pmd_mkwrite(pmd_t pmd)
 {
-       pmd_val(pmd) |= (_PAGE_WRITE | _PAGE_DIRTY);
+       pmd_val(pmd) |= _PAGE_WRITE;
+       if (pmd_val(pmd) & _PAGE_MODIFIED)
+               pmd_val(pmd) |= _PAGE_DIRTY;
        return pmd;
 }