+extern vm_size_t mem_size; /* 32-bit size of memory - limited by maxmem - deprecated */
+extern uint64_t max_mem; /* 64-bit size of memory - limited by maxmem */
+
+#ifdef XNU_KERNEL_PRIVATE
+
+extern uint64_t mem_actual; /* 64-bit size of memory - not limited by maxmem */
+extern uint64_t sane_size; /* Memory size to use for defaults calculations */
+extern addr64_t vm_last_addr; /* Highest kernel virtual address known to the VM system */
+
+extern const vm_offset_t vm_min_kernel_address;
+extern const vm_offset_t vm_max_kernel_address;
+
+#endif /* XNU_KERNEL_PRIVATE */
+
+extern vm_size_t page_size;
+extern vm_size_t page_mask;
+extern int page_shift;
+
+/* We need a way to get rid of compiler warnings when we cast from */
+/* a 64 bit value to an address that is 32 bits. */
+/* We know at this point the cast is harmless but sometime in */
+/* the future it may not be. */
+/* When size of an int is no longer equal to size of uintptr_t then */
+/* the compile will fail and we know we need to fix our cast. */
+#include <stdint.h>
+#ifndef __CAST_DOWN_CHECK
+#define __CAST_DOWN_CHECK
+typedef char __NEED_TO_CHANGE_CAST_DOWN[ sizeof(uintptr_t) == sizeof(int) ? 0 : -1 ];
+#define CAST_DOWN( type, addr ) ( ((type)((uintptr_t) (addr))) )
+#endif /* __CAST_DOWN_CHECK */