VDSO_NR_VCLOCK_PAGES
VDSO_NR_VCLOCK_PAGES * PAGE_SIZE,
static_assert(VDSO_NR_PAGES + VDSO_NR_VCLOCK_PAGES == __VDSO_PAGES);
#define VDSO_VCLOCK_PAGES_START(_b) ((_b) + (__VDSO_PAGES - VDSO_NR_VCLOCK_PAGES) * PAGE_SIZE)