[IA64-SGI] convert AMO address found in XPC's reserved page

This patch detects the existence of an uncached physical AMO address setup
by EFI's XPBOOT (SGI) and converts it to an uncached virtual AMO address.
Depends on a patch submitted on 23 March 2005 with the subject of:
    [PATCH 2/3] SGI Altix cross partition functionality (2nd revision)

Signed-off-by: Dean Nelson <dcn@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>

arch/ia64/sn/kernel/xpc_partition.c

@@ -204,6 +204,19 @@ xpc_rsvd_page_init(void)
 				return NULL;
 			}
 		}
+	} else if (!IS_AMO_ADDRESS((u64) amos_page)) {
+		/*
+		 * EFI's XPBOOT can also set amos_page in the reserved page,
+		 * but it happens to leave it as an uncached physical address
+		 * and we need it to be an uncached virtual, so we'll have to
+		 * convert it.
+		 */
+		if (!IS_AMO_PHYS_ADDRESS((u64) amos_page)) {
+			dev_err(xpc_part, "previously used amos_page address "
+				"is bad = 0x%p\n", (void *) amos_page);
+			return NULL;
+		}
+		amos_page = (AMO_t *) TO_AMO((u64) amos_page);
 	}
 
 	memset(xpc_vars, 0, sizeof(struct xpc_vars));
@@ -944,7 +957,7 @@ xpc_discovery(void)
 
 /*
  * Given a partid, get the nasids owned by that partition from the
- * remote partitions reserved page.
+ * remote partition's reserved page.
  */
 enum xpc_retval
 xpc_initiate_partid_to_nasids(partid_t partid, void *nasid_mask)

include/asm-ia64/sn/addrs.h

@@ -136,6 +136,7 @@
  */
 #define CAC_BASE		(CACHED   | AS_CAC_SPACE)
 #define AMO_BASE		(UNCACHED | AS_AMO_SPACE)
+#define AMO_PHYS_BASE		(UNCACHED_PHYS | AS_AMO_SPACE)
 #define GET_BASE		(CACHED   | AS_GET_SPACE)
 
 /*
@@ -160,6 +161,13 @@
 #define PHYS_TO_DMA(x)          ( (((u64)(x) & NASID_MASK) >> 2) | NODE_OFFSET(x))
 
 
+/*
+ * Macros to test for address type.
+ */
+#define IS_AMO_ADDRESS(x)	(((u64)(x) & (REGION_BITS | AS_MASK)) == AMO_BASE)
+#define IS_AMO_PHYS_ADDRESS(x)	(((u64)(x) & (REGION_BITS | AS_MASK)) == AMO_PHYS_BASE)
+
+
 /*
  * The following definitions pertain to the IO special address
  * space.  They define the location of the big and little windows