[S390] Memory detection fixes.

VMALLOC_END on 31bit should be 0x8000000UL instead of 0x7fffffffL.
The page mask which is used to make sure memory_end is on 4MB/2MB
boundary is wrong and not needed. Therefore remove it.
Make sure a vmalloc area does also exist and work on (future)
machines with 4TB and more memory.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 12 insertions, 3 deletions

diff --git a/include/asm-s390/pgtable.h b/include/asm-s390/pgtable.h
index 36bb6dacf008..2d968a69ed1f 100644
--- a/include/asm-s390/pgtable.h
+++ b/include/asm-s390/pgtable.h
@@ -110,13 +110,22 @@ extern char empty_zero_page[PAGE_SIZE];
 #define VMALLOC_OFFSET  (8*1024*1024)
 #define VMALLOC_START   (((unsigned long) high_memory + VMALLOC_OFFSET) \
                          & ~(VMALLOC_OFFSET-1))
+
+/*
+ * We need some free virtual space to be able to do vmalloc.
+ * VMALLOC_MIN_SIZE defines the minimum size of the vmalloc
+ * area. On a machine with 2GB memory we make sure that we
+ * have at least 128MB free space for vmalloc. On a machine
+ * with 4TB we make sure we have at least 1GB.
+ */
 #ifndef __s390x__
-# define VMALLOC_END     (0x7fffffffL)
+#define VMALLOC_MIN_SIZE        0x8000000UL
+#define VMALLOC_END             0x80000000UL
 #else /* __s390x__ */
-# define VMALLOC_END     (0x40000000000L)
+#define VMALLOC_MIN_SIZE        0x40000000UL
+#define VMALLOC_END             0x40000000000UL
 #endif /* __s390x__ */
 
-
 /*
  * A 31 bit pagetable entry of S390 has following format:
  *  |   PFRA          |    |  OS  |