diff --git a/libc/arch-x86_64/bionic/futex_x86_64.S b/libc/arch-x86_64/bionic/futex_x86_64.S
new file mode 100644
index 0000000..c248439
--- /dev/null
+++ b/libc/arch-x86_64/bionic/futex_x86_64.S
@@ -0,0 +1,37 @@
+/*
+ * Copyright (C) 2013 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *  * Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *  * Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <private/bionic_asm.h>
+
+// int __futex_syscall4(volatile void* ftx, int op, int val, const struct timespec* timeout)
+ENTRY_PRIVATE(__futex_syscall4)
+    mov     %rcx, %r10      /* timeout */
+    mov     $__NR_futex, %eax
+    syscall
+    ret
+END(__futex_syscall4)
diff --git a/libc/arch-x86_64/syscalls/futex.S b/libc/arch-x86_64/syscalls/futex.S
new file mode 100644
index 0000000..62f64bd
--- /dev/null
+++ b/libc/arch-x86_64/syscalls/futex.S
@@ -0,0 +1,17 @@
+/* Generated by gensyscalls.py. Do not edit. */
+
+#include <private/bionic_asm.h>
+
+ENTRY(futex)
+    movq    %rcx, %r10
+    movl    $__NR_futex, %eax
+    syscall
+    cmpq    $-MAX_ERRNO, %rax
+    jb      1f
+    negl    %eax
+    movl    %eax, %edi
+    call    __set_errno
+    orq     $-1, %rax
+1:
+    ret
+END(futex)
diff --git a/libc/arch-x86_64/x86_64.mk b/libc/arch-x86_64/x86_64.mk
index e3c2562..2bcf432 100644
--- a/libc/arch-x86_64/x86_64.mk
+++ b/libc/arch-x86_64/x86_64.mk
@@ -30,6 +30,7 @@
 libc_bionic_src_files_x86_64 := \
     arch-x86_64/bionic/__bionic_clone.S \
     arch-x86_64/bionic/_exit_with_stack_teardown.S \
+    arch-x86_64/bionic/futex_x86_64.S \
     arch-x86_64/bionic/__get_sp.S \
     arch-x86_64/bionic/__rt_sigreturn.S \
     arch-x86_64/bionic/_setjmp.S \