ppc32: Flush the Hash PTE in ptep_test_and_clear_young()

Without this, page aging is broken on ppc32

arch/ppc/mm/tlb.c

@@ -46,6 +46,26 @@ void flush_hash_entry(struct mm_struct *mm, pte_t *ptep, unsigned long addr)
 	}
 }
 
+/*
+ * Called by ptep_test_and_clear_young()
+ */
+void flush_hash_one_pte(pte_t *ptep)
+{
+	struct page *ptepage;
+	struct mm_struct *mm;
+	unsigned long ptephys;
+	unsigned long addr;
+
+	if (Hash == 0)
+		return;
+	
+	ptepage = virt_to_page(ptep);
+	mm = (struct mm_struct *) ptepage->mapping;
+	ptephys = __pa(ptep) & PAGE_MASK;
+	addr = ptepage->index + (((unsigned long)ptep & ~PAGE_MASK) << 9);
+	flush_hash_pages(mm->context, addr, ptephys, 1);
+}
+
 /*
  * Called at the end of a mmu_gather operation to make sure the
  * TLB flush is completely done.

include/asm-ppc/pgtable.h

@@ -511,9 +511,21 @@ static inline void set_pte(pte_t *ptep, pte_t pte)
 #endif
 }
 
+extern void flush_hash_one_pte(pte_t *ptep);
+
+/*
+ * 2.6 calles this without flushing the TLB entry, this is wrong
+ * for our hash-based implementation, we fix that up here
+ */
 static inline int ptep_test_and_clear_young(pte_t *ptep)
 {
-	return (pte_update(ptep, _PAGE_ACCESSED, 0) & _PAGE_ACCESSED) != 0;
+	unsigned long old;
+	old = (pte_update(ptep, _PAGE_ACCESSED, 0) & _PAGE_ACCESSED);
+#if _PAGE_HASHPTE != 0
+	if (old & _PAGE_HASHPTE)
+		flush_hash_one_pte(ptep);
+#endif
+	return old != 0;
 }
 
 static inline int ptep_test_and_clear_dirty(pte_t *ptep)