s390/mm,vmem: use 2GB frames for identity mapping

Use 2GB frames for indentity mapping if EDAT2 is
available to reduce TLB pressure.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h
index 2d3b7cb..0eefb9e 100644
--- a/arch/s390/include/asm/pgtable.h
+++ b/arch/s390/include/asm/pgtable.h
@@ -345,6 +345,8 @@
 #define _REGION3_ENTRY		(_REGION_ENTRY_TYPE_R3 | _REGION_ENTRY_LENGTH)
 #define _REGION3_ENTRY_EMPTY	(_REGION_ENTRY_TYPE_R3 | _REGION_ENTRY_INV)
 
+#define _REGION3_ENTRY_LARGE	0x400	/* RTTE-format control, large page  */
+
 /* Bits in the segment table entry */
 #define _SEGMENT_ENTRY_ORIGIN	~0x7ffUL/* segment table origin		    */
 #define _SEGMENT_ENTRY_RO	0x200	/* page protection bit		    */
@@ -444,6 +446,7 @@
 
 static inline int pud_present(pud_t pud) { return 1; }
 static inline int pud_none(pud_t pud)	 { return 0; }
+static inline int pud_large(pud_t pud)	 { return 0; }
 static inline int pud_bad(pud_t pud)	 { return 0; }
 
 #else /* CONFIG_64BIT */
@@ -489,6 +492,13 @@
 	return (pud_val(pud) & _REGION_ENTRY_INV) != 0UL;
 }
 
+static inline int pud_large(pud_t pud)
+{
+	if ((pud_val(pud) & _REGION_ENTRY_TYPE_MASK) != _REGION_ENTRY_TYPE_R3)
+		return 0;
+	return !!(pud_val(pud) & _REGION3_ENTRY_LARGE);
+}
+
 static inline int pud_bad(pud_t pud)
 {
 	/*