diff --git a/libc/arch-x86/bionic/futex_x86.S b/libc/arch-x86/bionic/futex_x86.S
new file mode 100644
index 0000000..94647ca
--- /dev/null
+++ b/libc/arch-x86/bionic/futex_x86.S
@@ -0,0 +1,16 @@
+#include <private/bionic_asm.h>
+
+// int __futex_syscall4(volatile void* ftx, int op, int val, const struct timespec* timeout)
+ENTRY_PRIVATE(__futex_syscall4)
+    pushl   %ebx
+    pushl   %esi
+    movl    12(%esp), %ebx      /* ftx */
+    movl    16(%esp), %ecx      /* op */
+    movl    20(%esp), %edx      /* val */
+    movl    24(%esp), %esi      /* timeout */
+    movl    $__NR_futex, %eax
+    int     $0x80
+    popl    %esi
+    popl    %ebx
+    ret
+END(__futex_syscall4)
diff --git a/libc/arch-x86/syscalls/futex.S b/libc/arch-x86/syscalls/futex.S
new file mode 100644
index 0000000..7a52913
--- /dev/null
+++ b/libc/arch-x86/syscalls/futex.S
@@ -0,0 +1,42 @@
+/* Generated by gensyscalls.py. Do not edit. */
+
+#include <private/bionic_asm.h>
+
+ENTRY(futex)
+    pushl   %ebx
+    pushl   %ecx
+    pushl   %edx
+    pushl   %esi
+    pushl   %edi
+    pushl   %ebp
+    .cfi_def_cfa_offset 24
+    .cfi_rel_offset ebx, 0
+    .cfi_rel_offset ecx, 4
+    .cfi_rel_offset edx, 8
+    .cfi_rel_offset esi, 12
+    .cfi_rel_offset edi, 16
+    .cfi_rel_offset ebp, 20
+    mov     28(%esp), %ebx
+    mov     32(%esp), %ecx
+    mov     36(%esp), %edx
+    mov     40(%esp), %esi
+    mov     44(%esp), %edi
+    mov     48(%esp), %ebp
+    movl    $__NR_futex, %eax
+    int     $0x80
+    cmpl    $-MAX_ERRNO, %eax
+    jb      1f
+    negl    %eax
+    pushl   %eax
+    call    __set_errno
+    addl    $4, %esp
+    orl     $-1, %eax
+1:
+    popl    %ebp
+    popl    %edi
+    popl    %esi
+    popl    %edx
+    popl    %ecx
+    popl    %ebx
+    ret
+END(futex)
diff --git a/libc/arch-x86/x86.mk b/libc/arch-x86/x86.mk
index aa183cb..34da0ce 100644
--- a/libc/arch-x86/x86.mk
+++ b/libc/arch-x86/x86.mk
@@ -23,6 +23,7 @@
 libc_bionic_src_files_x86 += \
     arch-x86/bionic/__bionic_clone.S \
     arch-x86/bionic/_exit_with_stack_teardown.S \
+    arch-x86/bionic/futex_x86.S \
     arch-x86/bionic/__get_sp.S \
     arch-x86/bionic/_setjmp.S \
     arch-x86/bionic/setjmp.S \