Index: pmap.c
===================================================================
--- pmap.c	(revision 234992)
+++ pmap.c	(working copy)
@@ -4576,9 +4576,54 @@
 int
 pmap_mincore(pmap_t pmap, vm_offset_t addr, vm_paddr_t *locked_pa)
 {
-	printf("pmap_mincore()\n");
-	
-	return (0);
+	struct l2_bucket *l2b;
+	pt_entry_t *ptep, pte;
+	vm_paddr_t pa;
+	vm_page_t m;
+	int val;
+	boolean_t managed;
+
+	PMAP_LOCK(pmap);
+retry:
+	l2b = pmap_get_l2_bucket(pmap, addr);
+        if (l2b == NULL) {
+                val = 0;
+                goto out;
+        }
+	ptep = &l2b->l2b_kva[l2pte_index(addr)];
+	pte = (ptep != NULL) ? *ptep : 0;
+	if (!l2pte_valid(pte)) {
+		val = 0;
+		goto out;
+	}
+	val = MINCORE_INCORE;
+	if (pte & L2_S_PROT_W)
+		val |= MINCORE_MODIFIED | MINCORE_MODIFIED_OTHER;
+        managed = false;
+	pa = l2pte_pa(pte);
+        m = PHYS_TO_VM_PAGE(pa);
+        if (m != NULL && !(m->oflags & VPO_UNMANAGED))
+                managed = true;
+	if (managed) {
+		/*
+		 * This may falsely report the given address as
+		 * MINCORE_REFERENCED.  Unfortunately, due to the lack of
+		 * per-PTE reference information, it is impossible to
+		 * determine if the address is MINCORE_REFERENCED.  
+		 */
+		if ((m->aflags & PGA_REFERENCED) != 0)
+			val |= MINCORE_REFERENCED | MINCORE_REFERENCED_OTHER;
+	}
+	if ((val & (MINCORE_MODIFIED_OTHER | MINCORE_REFERENCED_OTHER)) !=
+	    (MINCORE_MODIFIED_OTHER | MINCORE_REFERENCED_OTHER) && managed) {
+		/* Ensure that "PHYS_TO_VM_PAGE(pa)->object" doesn't change. */
+		if (vm_page_pa_tryrelock(pmap, pa, locked_pa))
+			goto retry;
+	} else
+out:
+		PA_UNLOCK_COND(*locked_pa);
+	PMAP_UNLOCK(pmap);
+	return (val);
 }