extern unsigned int rtas_data;
extern int mem_init_done; /* set on boot once kmalloc can be called */
extern int init_bootmem_done; /* set on !NUMA once bootmem is available */
-extern unsigned long memory_limit;
+extern phys_addr_t memory_limit;
extern unsigned long klimit;
extern void *alloc_maybe_bootmem(size_t size, gfp_t mask);