pgtable: add arch_has_hw_pte_young() fallback

Change-Id: Ie771d5cdd3044cbc4c9918fc1dace1ceb0358ed7
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>

diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h
index 660b70c..e5d4e2b 100644 (file)
--- a/include/asm-generic/pgtable.h
+++ b/include/asm-generic/pgtable.h
@@ -121,6 +121,19 @@ static inline int pmdp_clear_flush_young(struct vm_area_struct *vma,
 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 #endif
 
+#ifndef arch_has_hw_pte_young
+/*
+ * Return whether the accessed bit is supported on the local CPU.
+ *
+ * This stub assumes accessing through an old PTE triggers a page fault.
+ * Architectures that automatically set the access bit should overwrite it.
+ */
+static inline bool arch_has_hw_pte_young(void)
+{
+       return false;
+}
+#endif
+
 #ifndef __HAVE_ARCH_PTEP_GET_AND_CLEAR
 static inline pte_t ptep_get_and_clear(struct mm_struct *mm,
                                       unsigned long address,