/* PHYS_OFFSET - the physical address of the start of memory. */
#define PHYS_OFFSET ({ memstart_addr; })
+/*
+ * The maximum physical address that the linear direct mapping
+ * of system RAM can cover. (PAGE_OFFSET can be interpreted as
+ * a 2's complement signed quantity and negated to derive the
+ * maximum size of the linear mapping.)
+ */
+#define MAX_MEMBLOCK_ADDR ({ memstart_addr - PAGE_OFFSET - 1; })
+
/*
* PFNs are used to describe any physical page; this means
* PFN 0 == physical address 0.