[S390] Add four level page tables for CONFIG_64BIT=y.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 13 insertions, 1 deletions

diff --git a/arch/s390/mm/vmem.c b/arch/s390/mm/vmem.c
index 434491f8f47c..35d90a4720fd 100644
--- a/arch/s390/mm/vmem.c
+++ b/arch/s390/mm/vmem.c
@@ -69,7 +69,19 @@ static void __ref *vmem_alloc_pages(unsigned int order)
         return alloc_bootmem_pages((1 << order) * PAGE_SIZE);
 }
 
-#define vmem_pud_alloc()        ({ BUG(); ((pud_t *) NULL); })
+static inline pud_t *vmem_pud_alloc(void)
+{
+        pud_t *pud = NULL;
+
+#ifdef CONFIG_64BIT
+        pud = vmem_alloc_pages(2);
+        if (!pud)
+                return NULL;
+        pud_val(*pud) = _REGION3_ENTRY_EMPTY;
+        memcpy(pud + 1, pud, (PTRS_PER_PUD - 1)*sizeof(pud_t));
+#endif
+        return pud;
+}
 
 static inline pmd_t *vmem_pmd_alloc(void)
 {