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>
@@ -5445,6 +5449,57 @@
 	return ((void *)(va + offset));
 }
 
+void *pmap_mapacpi(vm_paddr_t pa, vm_size_t size); /* TODO: header */
+void *pmap_mapacpi(vm_paddr_t pa, vm_size_t size)
+{
+	vm_offset_t va, offset;
+	pd_entry_t *pde;
+	int i, lvl, ndesc, mode = VM_MEMATTR_DEVICE;
+	size_t efisz;
+	struct efi_map_header *efihdr;
+	struct efi_md *map, *p;
+	caddr_t kmdp;
+
+	/* Find mode using EFI (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);
+	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;
+	}
+
+	offset = pa & PAGE_MASK;
+	size = round_page(offset + size);
+
+	va = kva_alloc(size);
+	if (va == 0)
+		panic("%s: Couldn't allocate KVA", __func__);
+
+	pde = pmap_pde(kernel_pmap, va, &lvl);
+	KASSERT(lvl == 2, ("pmap_mapbios: Invalid level %d", lvl));
+
+	/* L3 table is linked */
+	va = trunc_page(va);
+	pa = trunc_page(pa);
+	pmap_kenter(va, size, pa, mode);
+
+	return ((void *)(va + offset));
+}
+
 void
 pmap_unmapbios(vm_offset_t va, vm_size_t size)
 {
Index: sys/dev/acpica/Osd/OsdMemory.c
===================================================================
--- sys/dev/acpica/Osd/OsdMemory.c
+++ sys/dev/acpica/Osd/OsdMemory.c
@@ -57,7 +57,8 @@
 void *
 AcpiOsMapMemory(ACPI_PHYSICAL_ADDRESS PhysicalAddress, ACPI_SIZE Length)
 {
-    return (pmap_mapbios((vm_offset_t)PhysicalAddress, Length));
+    extern void *pmap_mapacpi(vm_paddr_t pa, vm_size_t size); /* TODO: header */
+    return (pmap_mapacpi((vm_offset_t)PhysicalAddress, Length));
 }
 
 void