sparc64: Increase max_phys_bits to 51 and VA bits to 53 for M8.

On M8 chips, use a max_phys_bits value of 51.

Also, M8 supports VA bits up to 54 bits. However, for now
restrict VA bits to 53 due to 4-level pagetable limitation.

Signed-off-by: Vijay Kumar <vijay.ac.kumar@oracle.com>
Reviewed-by: Bob Picco <bob.picco@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/arch/sparc/mm/init_64.c b/arch/sparc/mm/init_64.c
index c24f4bf..afa0099 100644 (file)
--- a/arch/sparc/mm/init_64.c
+++ b/arch/sparc/mm/init_64.c
@@ -1944,12 +1944,22 @@ static void __init setup_page_offset(void)
                        break;
                case SUN4V_CHIP_SPARC_M7:
                case SUN4V_CHIP_SPARC_SN:
-               default:
                        /* M7 and later support 52-bit virtual addresses.  */
                        sparc64_va_hole_top =    0xfff8000000000000UL;
                        sparc64_va_hole_bottom = 0x0008000000000000UL;
                        max_phys_bits = 49;
                        break;
+               case SUN4V_CHIP_SPARC_M8:
+               default:
+                       /* M8 and later support 54-bit virtual addresses.
+                        * However, restricting M8 and above VA bits to 53
+                        * as 4-level page table cannot support more than
+                        * 53 VA bits.
+                        */
+                       sparc64_va_hole_top =    0xfff0000000000000UL;
+                       sparc64_va_hole_bottom = 0x0010000000000000UL;
+                       max_phys_bits = 51;
+                       break;
                }
        }