sparc64: Increase MAX_PHYS_ADDRESS_BITS to 53.

Make sure, at compile time, that the kernel can properly support
whatever MAX_PHYS_ADDRESS_BITS is defined to.

On M7 chips, use a max_phys_bits value of 49.

Based upon a patch by Bob Picco.

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

2 files changed, 8 insertions, 4 deletions

diff --git a/arch/sparc/include/asm/page_64.h b/arch/sparc/include/asm/page_64.h
index 732ba178a289..6784a3382826 100644
--- a/arch/sparc/include/asm/page_64.h
+++ b/arch/sparc/include/asm/page_64.h
@@ -122,11 +122,11 @@ extern unsigned long PAGE_OFFSET;
 
 #endif /* !(__ASSEMBLY__) */
 
-/* The maximum number of physical memory address bits we support, this
- * is used to size various tables used to manage kernel TLB misses and
- * also the sparsemem code.
+/* The maximum number of physical memory address bits we support.  The
+ * largest value we can support is whatever "KPGD_SHIFT + KPTE_BITS"
+ * evaluates to.
  */
-#define MAX_PHYS_ADDRESS_BITS   47
+#define MAX_PHYS_ADDRESS_BITS   53
 
 #define ILOG2_4MB               22
 #define ILOG2_256MB             28
diff --git a/arch/sparc/include/asm/pgtable_64.h b/arch/sparc/include/asm/pgtable_64.h
index a305b22ab581..0552957f6ddc 100644
--- a/arch/sparc/include/asm/pgtable_64.h
+++ b/arch/sparc/include/asm/pgtable_64.h
@@ -67,6 +67,10 @@
 #define PGDIR_MASK      (~(PGDIR_SIZE-1))
 #define PGDIR_BITS      (PAGE_SHIFT - 3)
 
+#if (MAX_PHYS_ADDRESS_BITS > PGDIR_SHIFT + PGDIR_BITS)
+#error MAX_PHYS_ADDRESS_BITS exceeds what kernel page tables can support
+#endif
+
 #if (PGDIR_SHIFT + PGDIR_BITS) != 53
 #error Page table parameters do not cover virtual address space properly.
 #endif