diff --git a/sys/amd64/amd64/pmap.c b/sys/amd64/amd64/pmap.c
--- a/sys/amd64/amd64/pmap.c
+++ b/sys/amd64/amd64/pmap.c
@@ -9304,12 +9304,16 @@
 					m = PHYS_TO_VM_PAGE(*pte & PG_FRAME);
 					vm_page_dirty(m);
 				}
-				atomic_clear_long(pte, PG_M | PG_A);
-			} else if ((*pte & PG_A) != 0)
-				atomic_clear_long(pte, PG_A);
-			else
+			} else
 				goto maybe_invlrng;
 
+			/*
+			 * Avoid clearing the accessed bit for wired mappings.
+			 * Superpage demotion assumes that a wired mapping is
+			 * always accessed.
+			 */
+			atomic_clear_long(pte,
+			    PG_M | ((*pte & PG_W) == 0 ? PG_A : 0));
 			if ((*pte & PG_G) != 0) {
 				if (va == va_next)
 					va = sva;
diff --git a/sys/arm64/arm64/pmap.c b/sys/arm64/arm64/pmap.c
--- a/sys/arm64/arm64/pmap.c
+++ b/sys/arm64/arm64/pmap.c
@@ -7695,7 +7695,7 @@
 					 * subsequent access may act as a
 					 * repromotion trigger.
 					 */
-                                        if ((oldl3 & ATTR_SW_WIRED) == 0) {
+					if ((oldl3 & ATTR_SW_WIRED) == 0) {
 						dva = MIN((sva & ~L3C_OFFSET) +
 						    L3C_SIZE - PAGE_SIZE,
 						    va_next - PAGE_SIZE);
@@ -7721,12 +7721,17 @@
 				 * we avoid corrupting the page able.
 				 */
 				if (oldl3 != 0) {
-					while (!atomic_fcmpset_long(l3, &oldl3,
-					    (oldl3 & ~ATTR_AF) |
-					    ATTR_S1_AP(ATTR_S1_AP_RO)))
-						cpu_spinwait();
+					if ((oldl3 & ATTR_SW_WIRED) != 0)
+						pmap_set_bits(l3,
+						    ATTR_S1_AP(ATTR_S1_AP_RO));
+					else
+						while (!atomic_fcmpset_long(l3,
+						    &oldl3, (oldl3 & ~ATTR_AF) |
+						    ATTR_S1_AP(ATTR_S1_AP_RO)))
+							cpu_spinwait();
 				}
-			} else if ((oldl3 & ATTR_AF) != 0) {
+			} else if ((oldl3 & (ATTR_AF | ATTR_SW_WIRED)) ==
+			    ATTR_AF) {
 				/*
 				 * Clear the accessed bit in this L3 entry
 				 * regardless of the contiguous bit.