diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 49395dc..5af55fc 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -245,7 +245,12 @@
 #define __NR_sys_rt_sigqueueinfo __NR_rt_sigqueueinfo
 #define __NR_sys_rt_tgsigqueueinfo __NR_rt_tgsigqueueinfo
 #define __NR_sys_syslog __NR_syslog
-#define __NR_sys_futex __NR_futex
+#if defined(__NR_futex)
+# define __NR_sys_futex __NR_futex
+#endif
+#if defined(__NR_futex_time64)
+# define __NR_sys_futex_time64 __NR_futex_time64
+#endif
 #define __NR_sys_inotify_init __NR_inotify_init
 #define __NR_sys_inotify_add_watch __NR_inotify_add_watch
 #define __NR_sys_inotify_rm_watch __NR_inotify_rm_watch
@@ -295,10 +300,14 @@
 #if defined(TARGET_NR_set_tid_address) && defined(__NR_set_tid_address)
 _syscall1(int,set_tid_address,int *,tidptr)
 #endif
-#if (defined(TARGET_NR_futex) || defined(TARGET_NR_exit)) && defined(__NR_futex)
+#if defined(__NR_futex)
 _syscall6(int,sys_futex,int *,uaddr,int,op,int,val,
           const struct timespec *,timeout,int *,uaddr2,int,val3)
 #endif
+#if defined(__NR_futex_time64)
+_syscall6(int,sys_futex_time64,int *,uaddr,int,op,int,val,
+          const struct timespec *,timeout,int *,uaddr2,int,val3)
+#endif
 #define __NR_sys_sched_getaffinity __NR_sched_getaffinity
 _syscall3(int, sys_sched_getaffinity, pid_t, pid, unsigned int, len,
           unsigned long *, user_mask_ptr);
@@ -762,10 +771,14 @@
 safe_syscall6(int, epoll_pwait, int, epfd, struct epoll_event *, events,
               int, maxevents, int, timeout, const sigset_t *, sigmask,
               size_t, sigsetsize)
-#ifdef TARGET_NR_futex
+#if defined(__NR_futex)
 safe_syscall6(int,futex,int *,uaddr,int,op,int,val, \
               const struct timespec *,timeout,int *,uaddr2,int,val3)
 #endif
+#if defined(__NR_futex_time64)
+safe_syscall6(int,futex_time64,int *,uaddr,int,op,int,val, \
+              const struct timespec *,timeout,int *,uaddr2,int,val3)
+#endif
 safe_syscall2(int, rt_sigsuspend, sigset_t *, newset, size_t, sigsetsize)
 safe_syscall2(int, kill, pid_t, pid, int, sig)
 safe_syscall2(int, tkill, int, tid, int, sig)
@@ -1229,7 +1242,7 @@
 }
 #endif
 
-#if defined(TARGET_NR_clock_settime64)
+#if defined(TARGET_NR_clock_settime64) || defined(TARGET_NR_futex_time64)
 static inline abi_long target_to_host_timespec64(struct timespec *host_ts,
                                                  abi_ulong target_addr)
 {
@@ -6916,6 +6929,55 @@
 }
 #endif
 
+static int do_sys_futex(int *uaddr, int op, int val,
+                         const struct timespec *timeout, int *uaddr2,
+                         int val3)
+{
+#if HOST_LONG_BITS == 64
+#if defined(__NR_futex)
+    /* always a 64-bit time_t, it doesn't define _time64 version  */
+    return sys_futex(uaddr, op, val, timeout, uaddr2, val3);
+
+#endif
+#else /* HOST_LONG_BITS == 64 */
+#if defined(__NR_futex_time64)
+    if (sizeof(timeout->tv_sec) == 8) {
+        /* _time64 function on 32bit arch */
+        return sys_futex_time64(uaddr, op, val, timeout, uaddr2, val3);
+    }
+#endif
+#if defined(__NR_futex)
+    /* old function on 32bit arch */
+    return sys_futex(uaddr, op, val, timeout, uaddr2, val3);
+#endif
+#endif /* HOST_LONG_BITS == 64 */
+    g_assert_not_reached();
+}
+
+static int do_safe_futex(int *uaddr, int op, int val,
+                         const struct timespec *timeout, int *uaddr2,
+                         int val3)
+{
+#if HOST_LONG_BITS == 64
+#if defined(__NR_futex)
+    /* always a 64-bit time_t, it doesn't define _time64 version  */
+    return get_errno(safe_futex(uaddr, op, val, timeout, uaddr2, val3));
+#endif
+#else /* HOST_LONG_BITS == 64 */
+#if defined(__NR_futex_time64)
+    if (sizeof(timeout->tv_sec) == 8) {
+        /* _time64 function on 32bit arch */
+        return get_errno(safe_futex_time64(uaddr, op, val, timeout, uaddr2,
+                                           val3));
+    }
+#endif
+#if defined(__NR_futex)
+    /* old function on 32bit arch */
+    return get_errno(safe_futex(uaddr, op, val, timeout, uaddr2, val3));
+#endif
+#endif /* HOST_LONG_BITS == 64 */
+    return -TARGET_ENOSYS;
+}
 
 /* ??? Using host futex calls even when target atomic operations
    are not really atomic probably breaks things.  However implementing
@@ -6945,12 +7007,11 @@
         } else {
             pts = NULL;
         }
-        return get_errno(safe_futex(g2h(uaddr), op, tswap32(val),
-                         pts, NULL, val3));
+        return do_safe_futex(g2h(uaddr), op, tswap32(val), pts, NULL, val3);
     case FUTEX_WAKE:
-        return get_errno(safe_futex(g2h(uaddr), op, val, NULL, NULL, 0));
+        return do_safe_futex(g2h(uaddr), op, val, NULL, NULL, 0);
     case FUTEX_FD:
-        return get_errno(safe_futex(g2h(uaddr), op, val, NULL, NULL, 0));
+        return do_safe_futex(g2h(uaddr), op, val, NULL, NULL, 0);
     case FUTEX_REQUEUE:
     case FUTEX_CMP_REQUEUE:
     case FUTEX_WAKE_OP:
@@ -6960,16 +7021,63 @@
            to satisfy the compiler.  We do not need to tswap TIMEOUT
            since it's not compared to guest memory.  */
         pts = (struct timespec *)(uintptr_t) timeout;
-        return get_errno(safe_futex(g2h(uaddr), op, val, pts,
-                                    g2h(uaddr2),
-                                    (base_op == FUTEX_CMP_REQUEUE
-                                     ? tswap32(val3)
-                                     : val3)));
+        return do_safe_futex(g2h(uaddr), op, val, pts, g2h(uaddr2),
+                             (base_op == FUTEX_CMP_REQUEUE
+                                      ? tswap32(val3)
+                                      : val3));
     default:
         return -TARGET_ENOSYS;
     }
 }
 #endif
+
+#if defined(TARGET_NR_futex_time64)
+static int do_futex_time64(target_ulong uaddr, int op, int val, target_ulong timeout,
+                           target_ulong uaddr2, int val3)
+{
+    struct timespec ts, *pts;
+    int base_op;
+
+    /* ??? We assume FUTEX_* constants are the same on both host
+       and target.  */
+#ifdef FUTEX_CMD_MASK
+    base_op = op & FUTEX_CMD_MASK;
+#else
+    base_op = op;
+#endif
+    switch (base_op) {
+    case FUTEX_WAIT:
+    case FUTEX_WAIT_BITSET:
+        if (timeout) {
+            pts = &ts;
+            target_to_host_timespec64(pts, timeout);
+        } else {
+            pts = NULL;
+        }
+        return do_safe_futex(g2h(uaddr), op, tswap32(val), pts, NULL, val3);
+    case FUTEX_WAKE:
+        return do_safe_futex(g2h(uaddr), op, val, NULL, NULL, 0);
+    case FUTEX_FD:
+        return do_safe_futex(g2h(uaddr), op, val, NULL, NULL, 0);
+    case FUTEX_REQUEUE:
+    case FUTEX_CMP_REQUEUE:
+    case FUTEX_WAKE_OP:
+        /* For FUTEX_REQUEUE, FUTEX_CMP_REQUEUE, and FUTEX_WAKE_OP, the
+           TIMEOUT parameter is interpreted as a uint32_t by the kernel.
+           But the prototype takes a `struct timespec *'; insert casts
+           to satisfy the compiler.  We do not need to tswap TIMEOUT
+           since it's not compared to guest memory.  */
+        pts = (struct timespec *)(uintptr_t) timeout;
+        return do_safe_futex(g2h(uaddr), op, val, pts, g2h(uaddr2),
+                             (base_op == FUTEX_CMP_REQUEUE
+                                      ? tswap32(val3)
+                                      : val3));
+    default:
+        return -TARGET_ENOSYS;
+    }
+}
+#endif
+
 #if defined(TARGET_NR_name_to_handle_at) && defined(CONFIG_OPEN_BY_HANDLE)
 static abi_long do_name_to_handle_at(abi_long dirfd, abi_long pathname,
                                      abi_long handle, abi_long mount_id,
@@ -7541,7 +7649,7 @@
             ts = cpu->opaque;
             if (ts->child_tidptr) {
                 put_user_u32(0, ts->child_tidptr);
-                sys_futex(g2h(ts->child_tidptr), FUTEX_WAKE, INT_MAX,
+                do_sys_futex(g2h(ts->child_tidptr), FUTEX_WAKE, INT_MAX,
                           NULL, NULL, 0);
             }
             thread_cpu = NULL;
@@ -11635,6 +11743,10 @@
     case TARGET_NR_futex:
         return do_futex(arg1, arg2, arg3, arg4, arg5, arg6);
 #endif
+#ifdef TARGET_NR_futex_time64
+    case TARGET_NR_futex_time64:
+        return do_futex_time64(arg1, arg2, arg3, arg4, arg5, arg6);
+#endif
 #if defined(TARGET_NR_inotify_init) && defined(__NR_inotify_init)
     case TARGET_NR_inotify_init:
         ret = get_errno(sys_inotify_init());