--- a/xpcom/reflect/xptcall/src/md/unix/Makefile.in
+++ b/xpcom/reflect/xptcall/src/md/unix/Makefile.in
@@ -10,16 +10,19 @@
 # Linux/ARM
 #
 ifeq ($(OS_ARCH),Linux)
 ifneq (,$(filter arm% sa110,$(OS_TEST)))
 CXXFLAGS += -O2
 endif
 endif
 
+ifeq ($(OS_TEST),aarch64)
+ASFILES := xptcinvoke_asm_aarch64.s xptcstubs_asm_aarch64.s
+endif
 ######################################################################
 # HPPA
 ######################################################################
 #
 # HP-UX/PA32
 #
 # for gas and gcc, check comment in xptcinvoke_asm_pa32.s
 ifeq ($(OS_ARCH),HP-UX)

--- a/xpcom/reflect/xptcall/src/md/unix/moz.build
+++ b/xpcom/reflect/xptcall/src/md/unix/moz.build
@@ -144,16 +144,21 @@ if CONFIG['OS_ARCH'] == 'NetBSD':
     if CONFIG['OS_TEST'] in ('amiga', 'atari', 'hp300', 'mac68k', 'mvme68k',
                              'next68k', 'sun3', 'sun3x', 'x68k'):
         SOURCES += [
             'xptcinvoke_netbsd_m68k.cpp',
             'xptcstubs_netbsd_m68k.cpp'
         ]
 
 if CONFIG['OS_ARCH'] == 'Linux':
+    if CONFIG['OS_TEST'] == 'aarch64':
+        SOURCES += [
+            'xptcinvoke_aarch64.cpp',
+            'xptcstubs_aarch64.cpp',
+        ]
     if CONFIG['OS_TEST'] == 'm68k':
         SOURCES += [
             'xptcinvoke_linux_m68k.cpp',
             'xptcstubs_linux_m68k.cpp',
         ]
     if CONFIG['OS_TEST'].find('mips') != -1:
         if CONFIG['OS_TEST'].find('mips64') != -1:
             SOURCES += [