Index: sys/kern/subr_physmem.c
===================================================================
--- sys/kern/subr_physmem.c
+++ sys/kern/subr_physmem.c
@@ -68,6 +68,19 @@
 #define	MAX_PHYS_ADDR	0xFFFFFFFFFFFFFFFFull
 #endif
 
+#if defined(__aarch64__)
+/*
+ * The arm64 DMAP code assumes L2 block aligned & sized memory. Becauese of
+ * this round memory regions so the start and end are aligned to an L2 block
+ * boundary.
+ */
+#define	round_mem(x)	roundup2((x), L2_SIZE)
+#define	truncate_mem(x)	rounddown2((x), L2_SIZE)
+#else
+#define	round_mem(x)	round_page(x)
+#define	truncate_mem(x)	truncate_page(x)
+#endif
+
 struct region {
 	vm_paddr_t	addr;
 	vm_size_t	size;
@@ -351,9 +364,9 @@
 	 * Round the starting address up to a page boundary, and truncate the
 	 * ending page down to a page boundary.
 	 */
-	adj = round_page(pa) - pa;
-	pa  = round_page(pa);
-	sz  = trunc_page(sz - adj);
+	adj = round_mem(pa) - pa;
+	pa  = round_mem(pa);
+	sz  = trunc_mem(sz - adj);
 
 	if (sz > 0 && hwcnt < nitems(hwregions))
 		hwcnt = insert_region(hwregions, hwcnt, pa, sz, 0);
@@ -371,9 +384,9 @@
 	 * Truncate the starting address down to a page boundary, and round the
 	 * ending page up to a page boundary.
 	 */
-	adj = pa - trunc_page(pa);
-	pa  = trunc_page(pa);
-	sz  = round_page(sz + adj);
+	adj = pa - trunc_mem(pa);
+	pa  = trunc_mem(pa);
+	sz  = round_mem(sz + adj);
 
 	if (excnt >= nitems(exregions))
 		panic("failed to exclude region %#jx-%#jx", (uintmax_t)pa,