extern int e820_any_non_reserved(unsigned long start, unsigned long end);
extern int is_memory_any_valid(unsigned long start, unsigned long end);
extern int e820_all_non_reserved(unsigned long start, unsigned long end);
extern int e820_any_non_reserved(unsigned long start, unsigned long end);
extern int is_memory_any_valid(unsigned long start, unsigned long end);
extern int e820_all_non_reserved(unsigned long start, unsigned long end);