s390: expose number of page table levels

We would want to use number of page table level to define mm_struct.
Let's expose it as CONFIG_PGTABLE_LEVELS.

Core mm expects __PAGETABLE_{PUD,PMD}_FOLDED to be defined if these page
table levels folded.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index 373cd5b..f6aebcb 100644 (file)
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -155,6 +155,11 @@ config S390
 config SCHED_OMIT_FRAME_POINTER
        def_bool y
 
+config PGTABLE_LEVELS
+       int
+       default 4 if 64BIT
+       default 2
+
 source "init/Kconfig"
 
 source "kernel/Kconfig.freezer"