*/
static unsigned long sparse_encode_mem_map(struct page *mem_map, unsigned long pnum)
{
- return (unsigned long)(mem_map - (section_nr_to_pfn(pnum)));
+ unsigned long coded_mem_map =
+ (unsigned long)(mem_map - (section_nr_to_pfn(pnum)));
+ BUILD_BUG_ON(SECTION_MAP_LAST_BIT > (1UL<<PFN_SECTION_SHIFT));
+ BUG_ON(coded_mem_map & ~SECTION_MAP_MASK);
+ return coded_mem_map;
}
/*