#define page_to_bus(page) (page_to_phys(page))
#define phys_to_page(paddr) (pfn_to_page(phys_to_pfn(paddr)))
+#define sym_to_pfn(x) __phys_to_pfn(__pa_symbol(x))
+
#ifdef CONFIG_FLATMEM
#define pfn_valid(pfn) \
(((pfn) >= ARCH_PFN_OFFSET) && (((pfn) - ARCH_PFN_OFFSET) < max_mapnr))