#define phys_to_pfn(p) ((p) >> PAGE_SHIFT)
#define pfn_to_phys(pfn) ((pfn) << PAGE_SHIFT)
#define pfn_valid(pfn) ((pfn) < max_mapnr)
#define virt_addr_valid(v) pfn_valid(phys_to_pfn(__pa(v)))
#define phys_to_pfn(p) ((p) >> PAGE_SHIFT)
#define pfn_to_phys(pfn) ((pfn) << PAGE_SHIFT)
#define pfn_valid(pfn) ((pfn) < max_mapnr)
#define virt_addr_valid(v) pfn_valid(phys_to_pfn(__pa(v)))