sparc64: Clean up 64-bit mmap exclusion defines.

Older UltraSPARC chips had an address space hole due to the MMU only
supporting 44-bit virtual addresses.

The top end of this hole also has the same value as the current
definition of PAGE_OFFSET, so this can be confusing.

Consolidate the defines for the userspace mmap exclusion range into
page_64.h and use them in sys_sparc_64.c and hugetlbpage.c

Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Bob Picco <bob.picco@oracle.com>

1 files changed, 15 insertions, 2 deletions

diff --git a/arch/sparc/include/asm/page_64.h b/arch/sparc/include/asm/page_64.h
index e15538899f3d..d95931247feb 100644
--- a/arch/sparc/include/asm/page_64.h
+++ b/arch/sparc/include/asm/page_64.h
@@ -93,9 +93,22 @@ typedef unsigned long pgprot_t;
 
 typedef pte_t *pgtable_t;
 
+/* These two values define the virtual address space range in which we
+ * must forbid 64-bit user processes from making mappings.  It
+ * represents the virtual address space hole present in most early
+ * sparc64 chips including UltraSPARC-I.  The next two defines specify
+ * the actual exclusion region we enforce, wherein we use a 4GB red
+ * zone on each side of the VA hole.
+ */
+#define SPARC64_VA_HOLE_TOP     _AC(0xfffff80000000000,UL)
+#define SPARC64_VA_HOLE_BOTTOM  _AC(0x0000080000000000,UL)
+
+#define VA_EXCLUDE_START (SPARC64_VA_HOLE_BOTTOM - (1UL << 32UL))
+#define VA_EXCLUDE_END   (SPARC64_VA_HOLE_TOP + (1UL << 32UL))
+
 #define TASK_UNMAPPED_BASE      (test_thread_flag(TIF_32BIT) ? \
-                                 (_AC(0x0000000070000000,UL)) : \
-                                 (_AC(0xfffff80000000000,UL) + (1UL << 32UL)))
+                                 _AC(0x0000000070000000,UL) : \
+                                 VA_EXCLUDE_END)
 
 #include <asm-generic/memory_model.h>