zero_pfn 861 include/asm-generic/pgtable.h extern unsigned long zero_pfn; zero_pfn 862 include/asm-generic/pgtable.h unsigned long offset_from_zero_pfn = pfn - zero_pfn; zero_pfn 871 include/asm-generic/pgtable.h extern unsigned long zero_pfn; zero_pfn 872 include/asm-generic/pgtable.h return pfn == zero_pfn; zero_pfn 877 include/asm-generic/pgtable.h extern unsigned long zero_pfn; zero_pfn 878 include/asm-generic/pgtable.h return zero_pfn; zero_pfn 128 mm/memory.c unsigned long zero_pfn __read_mostly; zero_pfn 129 mm/memory.c EXPORT_SYMBOL(zero_pfn); zero_pfn 138 mm/memory.c zero_pfn = page_to_pfn(ZERO_PAGE(0));