powerpc: New hugepage directory format
Change the hugepage directory format so that we can have leaf ptes directly
at page directory avoiding the allocation of hugepage directory.
With the new table format we have 3 cases for pgds and pmds:
(1) invalid (all zeroes)
(2) pointer to next table, as normal; bottom 6 bits == 0
(4) hugepd pointer, bottom two bits == 00, next 4 bits indicate size of table
Instead of storing shift value in hugepd pointer we use mmu_psize_def index
so that we can fit all the supported hugepage size in 4 bits
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/include/asm/pgalloc-64.h b/arch/powerpc/include/asm/pgalloc-64.h
index 292725c..69e352a 100644
--- a/arch/powerpc/include/asm/pgalloc-64.h
+++ b/arch/powerpc/include/asm/pgalloc-64.h
@@ -35,7 +35,10 @@
#define MAX_PGTABLE_INDEX_SIZE 0xf
extern struct kmem_cache *pgtable_cache[];
-#define PGT_CACHE(shift) (pgtable_cache[(shift)-1])
+#define PGT_CACHE(shift) ({ \
+ BUG_ON(!(shift)); \
+ pgtable_cache[(shift) - 1]; \
+ })
static inline pgd_t *pgd_alloc(struct mm_struct *mm)
{