Function pmap_page_set_memattr

freebsd/mips/mips/pmap.c:3655–3672

}

void
pmap_page_set_memattr(vm_page_t m, vm_memattr_t ma)
{

	/*
	 * It appears that this function can only be called before any mappings
	 * for the page are established.  If this ever changes, this code will
	 * need to walk the pv_list and make each of the existing mappings
	 * uncacheable, being careful to sync caches and PTEs (and maybe
	 * invalidate TLB?) for any current mapping it modifies.
	 */
	if (TAILQ_FIRST(&m->md.pv_list) != NULL)
		panic("Can't change memattr on page with existing mappings");

	/* Clean memattr portion of pv_flags */
	m->md.pv_flags &= ~PV_MEMATTR_MASK;
	m->md.pv_flags |= (ma << PV_MEMATTR_SHIFT) & PV_MEMATTR_MASK;
}

static __inline void
pmap_pte_attr(pt_entry_t *pte, vm_memattr_t ma)