PGD_T_LOG2        262 arch/mips/include/asm/pgtable.h #define PGD_T_LOG2	(__builtin_ffs(sizeof(pgd_t)) - 1)
PGD_T_LOG2         63 arch/powerpc/include/asm/page_32.h #define PGD_T_LOG2	(__builtin_ffs(sizeof(pgd_t)) - 1)