sparc64: Multi-page size support

Add support for using multiple hugepage sizes simultaneously
on mainline. Currently, support for 256M has been added which
can be used along with 8M pages.

Page tables are set like this (e.g. for 256M page):
    VA + (8M * x) -> PA + (8M * x) (sz bit = 256M) where x in [0, 31]

and TSB is set similarly:
    VA + (4M * x) -> PA + (4M * x) (sz bit = 256M) where x in [0, 63]

- Testing

Tested on Sonoma (which supports 256M pages) by running stream
benchmark instances in parallel: one instance uses 8M pages and
another uses 256M pages, consuming 48G each.

Boot params used:

default_hugepagesz=256M hugepagesz=256M hugepages=300 hugepagesz=8M
hugepages=10000

Signed-off-by: Nitin Gupta <nitin.m.gupta@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/arch/sparc/include/asm/page_64.h b/arch/sparc/include/asm/page_64.h
index c1263fc..d76f38d 100644
--- a/arch/sparc/include/asm/page_64.h
+++ b/arch/sparc/include/asm/page_64.h
@@ -17,7 +17,7 @@
 
 #define HPAGE_SHIFT		23
 #define REAL_HPAGE_SHIFT	22
-
+#define HPAGE_256MB_SHIFT	28
 #define REAL_HPAGE_SIZE		(_AC(1,UL) << REAL_HPAGE_SHIFT)
 
 #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
@@ -26,6 +26,7 @@
 #define HUGETLB_PAGE_ORDER	(HPAGE_SHIFT - PAGE_SHIFT)
 #define HAVE_ARCH_HUGETLB_UNMAPPED_AREA
 #define REAL_HPAGE_PER_HPAGE	(_AC(1,UL) << (HPAGE_SHIFT - REAL_HPAGE_SHIFT))
+#define HUGE_MAX_HSTATE		2
 #endif
 
 #ifndef __ASSEMBLY__