A pointer to the system page
#include <sys/syspage.h> struct syspage_entry *_syspage_ptr
This global variable holds a pointer to the system page, which contains information about the system, including the processor type, bus type, and the location and size of available system RAM. For information about this structure, see the Customizing Image Startup Programs chapter of Building Embedded Systems.
The best way to reference the system information page is via the kernel calls and POSIX cover functions. If there isn't a function to access the information you need, you should use the SYSPAGE_ENTRY() and SYSPAGE_CPU_ENTRY() macros instead of referencing the _syspage_ptr variable directly.