3 files changed, 33 insertions, 12 deletions
diff --git a/library/std/src/sys/sgx/mod.rs b/library/std/src/sys/sgx/mod.rs
index 01e4ffe3d..9865a945b 100644
--- a/library/std/src/sys/sgx/mod.rs
+++ b/library/std/src/sys/sgx/mod.rs
@@ -34,6 +34,7 @@ pub mod process;
 pub mod stdio;
 pub mod thread;
 pub mod thread_local_key;
+pub mod thread_parking;
 pub mod time;
 
 mod condvar;
diff --git a/library/std/src/sys/sgx/thread.rs b/library/std/src/sys/sgx/thread.rs
index d745a6196..1608b8cb6 100644
--- a/library/std/src/sys/sgx/thread.rs
+++ b/library/std/src/sys/sgx/thread.rs
@@ -65,39 +65,36 @@ mod task_queue {
 /// execution. The signal is sent once all TLS destructors have finished at
 /// which point no new thread locals should be created.
 pub mod wait_notify {
-    use super::super::waitqueue::{SpinMutex, WaitQueue, WaitVariable};
+    use crate::pin::Pin;
     use crate::sync::Arc;
+    use crate::sys_common::thread_parking::Parker;
 
-    pub struct Notifier(Arc<SpinMutex<WaitVariable<bool>>>);
+    pub struct Notifier(Arc<Parker>);
 
     impl Notifier {
         /// Notify the waiter. The waiter is either notified right away (if
         /// currently blocked in `Waiter::wait()`) or later when it calls the
         /// `Waiter::wait()` method.
         pub fn notify(self) {
-            let mut guard = self.0.lock();
-            *guard.lock_var_mut() = true;
-            let _ = WaitQueue::notify_one(guard);
+            Pin::new(&*self.0).unpark()
         }
     }
 
-    pub struct Waiter(Arc<SpinMutex<WaitVariable<bool>>>);
+    pub struct Waiter(Arc<Parker>);
 
     impl Waiter {
         /// Wait for a notification. If `Notifier::notify()` has already been
         /// called, this will return immediately, otherwise the current thread
         /// is blocked until notified.
         pub fn wait(self) {
-            let guard = self.0.lock();
-            if *guard.lock_var() {
-                return;
-            }
-            WaitQueue::wait(guard, || {});
+            // SAFETY:
+            // This is only ever called on one thread.
+            unsafe { Pin::new(&*self.0).park() }
         }
     }
 
     pub fn new() -> (Notifier, Waiter) {
-        let inner = Arc::new(SpinMutex::new(WaitVariable::new(false)));
+        let inner = Arc::new(Parker::new());
         (Notifier(inner.clone()), Waiter(inner))
     }
 }
diff --git a/library/std/src/sys/sgx/thread_parking.rs b/library/std/src/sys/sgx/thread_parking.rs
new file mode 100644
index 000000000..0006cd4f1
--- /dev/null
+++ b/library/std/src/sys/sgx/thread_parking.rs
@@ -0,0 +1,23 @@
+use super::abi::usercalls;
+use crate::io::ErrorKind;
+use crate::time::Duration;
+use fortanix_sgx_abi::{EV_UNPARK, WAIT_INDEFINITE};
+
+pub type ThreadId = fortanix_sgx_abi::Tcs;
+
+pub use super::abi::thread::current;
+
+pub fn park(_hint: usize) {
+    usercalls::wait(EV_UNPARK, WAIT_INDEFINITE).unwrap();
+}
+
+pub fn park_timeout(dur: Duration, _hint: usize) {
+    let timeout = u128::min(dur.as_nanos(), WAIT_INDEFINITE as u128 - 1) as u64;
+    if let Err(e) = usercalls::wait(EV_UNPARK, timeout) {
+        assert!(matches!(e.kind(), ErrorKind::TimedOut | ErrorKind::WouldBlock))
+    }
+}
+
+pub fn unpark(tid: ThreadId, _hint: usize) {
+    let _ = usercalls::send(EV_UNPARK, Some(tid));
+}