diff options
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/arm64/include/asm/pgtable.h | 33 |
1 files changed, 18 insertions, 15 deletions
diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h index 149d05fb9421..3ff03a755c32 100644 --- a/arch/arm64/include/asm/pgtable.h +++ b/arch/arm64/include/asm/pgtable.h @@ -149,12 +149,20 @@ static inline pte_t pte_mkwrite(pte_t pte) static inline pte_t pte_mkclean(pte_t pte) { - return clear_pte_bit(pte, __pgprot(PTE_DIRTY)); + pte = clear_pte_bit(pte, __pgprot(PTE_DIRTY)); + pte = set_pte_bit(pte, __pgprot(PTE_RDONLY)); + + return pte; } static inline pte_t pte_mkdirty(pte_t pte) { - return set_pte_bit(pte, __pgprot(PTE_DIRTY)); + pte = set_pte_bit(pte, __pgprot(PTE_DIRTY)); + + if (pte_write(pte)) + pte = clear_pte_bit(pte, __pgprot(PTE_RDONLY)); + + return pte; } static inline pte_t pte_mkold(pte_t pte) @@ -641,28 +649,23 @@ static inline pmd_t pmdp_huge_get_and_clear(struct mm_struct *mm, #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ /* - * ptep_set_wrprotect - mark read-only while preserving the hardware update of - * the Access Flag. + * ptep_set_wrprotect - mark read-only while trasferring potential hardware + * dirty status (PTE_DBM && !PTE_RDONLY) to the software PTE_DIRTY bit. */ #define __HAVE_ARCH_PTEP_SET_WRPROTECT static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long address, pte_t *ptep) { pte_t old_pte, pte; - /* - * ptep_set_wrprotect() is only called on CoW mappings which are - * private (!VM_SHARED) with the pte either read-only (!PTE_WRITE && - * PTE_RDONLY) or writable and software-dirty (PTE_WRITE && - * !PTE_RDONLY && PTE_DIRTY); see is_cow_mapping() and - * protection_map[]. There is no race with the hardware update of the - * dirty state: clearing of PTE_RDONLY when PTE_WRITE (a.k.a. PTE_DBM) - * is set. - */ - VM_WARN_ONCE(pte_write(*ptep) && !pte_dirty(*ptep), - "%s: potential race with hardware DBM", __func__); 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)); |