s390/hugetlb: add hugepages_supported define

On s390 we only can enable hugepages if the underlying hardware/hypervisor
also does support this.  Common code now would assume this to be
signaled by setting HPAGE_SHIFT to 0.  But on s390, where we only
support one hugepage size, there is a link between HPAGE_SHIFT and
pageblock_order.

So instead of setting HPAGE_SHIFT to 0, we will implement the check for
the hardware capability.

Signed-off-by: Dominik Dingel <[email protected]>
Acked-by: Martin Schwidefsky <[email protected]>
Cc: Heiko Carstens <[email protected]>
Cc: Christian Borntraeger <[email protected]>
Cc: Michael Holzheu <[email protected]>
Cc: Gerald Schaefer <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

diff --git a/arch/s390/include/asm/hugetlb.h b/arch/s390/include/asm/hugetlb.h
index 0130d0379edd179e8b06dbd459066b8606517676..d9be7c0c1291445cfb2356d88b973398fea67b97 100644 (file)
--- a/arch/s390/include/asm/hugetlb.h
+++ b/arch/s390/include/asm/hugetlb.h
@@ -14,6 +14,7 @@
 
 #define is_hugepage_only_range(mm, addr, len)  0
 #define hugetlb_free_pgd_range                 free_pgd_range
+#define hugepages_supported()                  (MACHINE_HAS_HPAGE)
 
 void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
                     pte_t *ptep, pte_t pte);