Index: head/sys/arm64/include/elf.h
===================================================================
--- head/sys/arm64/include/elf.h
+++ head/sys/arm64/include/elf.h
@@ -64,7 +64,11 @@
 
 __ElfType(Auxinfo);
 
+#ifdef _MACHINE_ELF_WANT_32BIT
+#define	ELF_ARCH	EM_ARM
+#else
 #define	ELF_ARCH	EM_AARCH64
+#endif
 
 #define	ELF_MACHINE_OK(x) ((x) == (ELF_ARCH))
 
Index: head/usr.bin/gcore/Makefile
===================================================================
--- head/usr.bin/gcore/Makefile
+++ head/usr.bin/gcore/Makefile
@@ -5,7 +5,7 @@
 SRCS=	elfcore.c gcore.c
 LIBADD=	sbuf util
 
-.if ${MACHINE_ARCH} == "amd64"
+.if ${MACHINE_ARCH} == "aarch64" || ${MACHINE_ARCH} == "amd64"
 SRCS+=	elf32core.c
 .endif
 
Index: head/usr.bin/gcore/elf32core.c
===================================================================
--- head/usr.bin/gcore/elf32core.c
+++ head/usr.bin/gcore/elf32core.c
@@ -32,7 +32,15 @@
 	rd->r_eflags = rs->r_rflags;
 	rd->r_esp = rs->r_rsp;
 	rd->r_ss = rs->r_ss;
-#else
+#elif defined(__aarch64__)
+	int i;
+
+	for (i = 0; i < 13; i++)
+		rd->r[i] = rs->x[i];
+	rd->r_sp = rs->x[13];
+	rd->r_lr = rs->x[14];
+	rd->r_pc = rs->elr;
+	rd->r_cpsr = rs->spsr;
 #error Unsupported architecture
 #endif
 }
@@ -43,6 +51,8 @@
 #ifdef __amd64__
 	/* XXX this is wrong... */
 	memcpy(rd, rs, sizeof(*rd));
+#elif defined(__aarch64__)
+	/* ARM64TODO */
 #else
 #error Unsupported architecture
 #endif