KERNEL_VSIDBITS
#define KERNEL2_SEGMENT VSID_MAKE(KERNEL2_SR, KERNEL_VSIDBITS)
#define KERNEL_SEGMENT VSID_MAKE(KERNEL_SR, KERNEL_VSIDBITS)
#define KERNELN_SEGMENT(s) VSID_MAKE(s, KERNEL_VSIDBITS)
pmap_vsid_bitmap[(KERNEL_VSIDBITS & (NPMAPS-1)) / VSID_NBPW]
|= 1 << (KERNEL_VSIDBITS % VSID_NBPW);
pmap_kernel()->pm_vsid = KERNEL_VSIDBITS;