Index: sys/arm64/arm64/pmap.c
===================================================================
--- sys/arm64/arm64/pmap.c
+++ sys/arm64/arm64/pmap.c
@@ -110,10 +110,12 @@
 #include <sys/param.h>
 #include <sys/bitstring.h>
 #include <sys/bus.h>
+#include <sys/efi.h>
 #include <sys/systm.h>
 #include <sys/kernel.h>
 #include <sys/ktr.h>
 #include <sys/limits.h>
+#include <sys/linker.h>
 #include <sys/lock.h>
 #include <sys/malloc.h>
 #include <sys/mman.h>
@@ -145,6 +147,8 @@
 #include <vm/vm_reserv.h>
 #include <vm/uma.h>
 
+#include <machine/efi.h>
+#include <machine/metadata.h>
 #include <machine/machdep.h>
 #include <machine/md_var.h>
 #include <machine/pcb.h>
@@ -355,6 +359,7 @@
 static void pmap_abort_ptp(pmap_t pmap, vm_offset_t va, vm_page_t mpte);
 static bool pmap_activate_int(pmap_t pmap);
 static void pmap_alloc_asid(pmap_t pmap);
+static int efi_find_mode(vm_paddr_t pa);
 static int pmap_change_attr_locked(vm_offset_t va, vm_size_t size, int mode);
 static pt_entry_t *pmap_demote_l1(pmap_t pmap, pt_entry_t *l1, vm_offset_t va);
 static pt_entry_t *pmap_demote_l2_locked(pmap_t pmap, pt_entry_t *l2,
@@ -5439,12 +5444,53 @@
 		/* L3 table is linked */
 		va = trunc_page(va);
 		pa = trunc_page(pa);
-		pmap_kenter(va, size, pa, VM_MEMATTR_WRITE_BACK);
+		pmap_kenter(va, size, pa, efi_find_mode(pa));
 	}
 
 	return ((void *)(va + offset));
 }
 
+static int efi_find_mode(vm_paddr_t pa)
+{
+	int i, ndesc, mode = VM_MEMATTR_DEVICE;
+	size_t efisz;
+	struct efi_map_header *efihdr;
+	struct efi_md *map, *p;
+	caddr_t kmdp;
+
+	/* TODO: don't search preload etc. on every call */
+	kmdp = preload_search_by_type("elf kernel");
+
+	efihdr = (struct efi_map_header *)preload_search_info(kmdp,
+	    MODINFO_METADATA | MODINFOMD_EFI_MAP);
+
+	if (efihdr == NULL) {
+		printf("pmap: EFI header not found\n");
+		return VM_MEMATTR_WRITE_BACK;
+	}
+
+	efisz = (sizeof(struct efi_map_header) + 0xf) & ~0xf;
+	map = (struct efi_md *)((uint8_t *)efihdr + efisz);
+	ndesc = efihdr->memory_size / efihdr->descriptor_size;
+
+	for (i = 0, p = map; i < ndesc; i++, p = efi_next_descriptor(p,
+	    efihdr->descriptor_size)) {
+		if (pa < p->md_phys || pa >= p->md_phys + p->md_pages * EFI_PAGE_SIZE)
+			continue;
+		if (p->md_type == EFI_MD_TYPE_IOMEM || p->md_type == EFI_MD_TYPE_IOPORT)
+			mode = VM_MEMATTR_DEVICE;
+		else if ((p->md_attr & EFI_MD_ATTR_WB) != 0 || p->md_type == EFI_MD_TYPE_RECLAIM)
+			mode = VM_MEMATTR_WRITE_BACK;
+		else if ((p->md_attr & EFI_MD_ATTR_WT) != 0)
+			mode = VM_MEMATTR_WRITE_THROUGH;
+		else if ((p->md_attr & EFI_MD_ATTR_WC) != 0)
+			mode = VM_MEMATTR_WRITE_COMBINING;
+		break;
+	}
+
+	return mode;
+}
+
 void
 pmap_unmapbios(vm_offset_t va, vm_size_t size)
 {