1 files changed, 76 insertions, 0 deletions
diff --git a/libgo/go/runtime/os_openbsd.go b/libgo/go/runtime/os_openbsd.go
new file mode 100644
index 00000000000..b64d3af385f
--- /dev/null
+++ b/libgo/go/runtime/os_openbsd.go
@@ -0,0 +1,76 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package runtime
+
+import (
+	"runtime/internal/atomic"
+	"unsafe"
+)
+
+type mOS struct {
+	waitsemacount uint32
+}
+
+//go:noescape
+//extern thrsleep
+func thrsleep(ident uintptr, clock_id int32, tsp *timespec, lock uintptr, abort *uint32) int32
+
+//go:noescape
+//extern thrwakeup
+func thrwakeup(ident uintptr, n int32) int32
+
+//go:nosplit
+func semacreate(mp *m) {
+}
+
+//go:nosplit
+func semasleep(ns int64) int32 {
+	_g_ := getg()
+
+	// Compute sleep deadline.
+	var tsp *timespec
+	if ns >= 0 {
+		var ts timespec
+		var nsec int32
+		ns += nanotime()
+		ts.set_sec(int64(timediv(ns, 1000000000, &nsec)))
+		ts.set_nsec(nsec)
+		tsp = &ts
+	}
+
+	for {
+		v := atomic.Load(&_g_.m.mos.waitsemacount)
+		if v > 0 {
+			if atomic.Cas(&_g_.m.mos.waitsemacount, v, v-1) {
+				return 0 // semaphore acquired
+			}
+			continue
+		}
+
+		// Sleep until woken by semawakeup or timeout; or abort if waitsemacount != 0.
+		//
+		// From OpenBSD's __thrsleep(2) manual:
+		// "The abort argument, if not NULL, points to an int that will
+		// be examined [...] immediately before blocking. If that int
+		// is non-zero then __thrsleep() will immediately return EINTR
+		// without blocking."
+		ret := thrsleep(uintptr(unsafe.Pointer(&_g_.m.mos.waitsemacount)), _CLOCK_MONOTONIC, tsp, 0, &_g_.m.mos.waitsemacount)
+		if ret == _EWOULDBLOCK {
+			return -1
+		}
+	}
+}
+
+//go:nosplit
+func semawakeup(mp *m) {
+	atomic.Xadd(&mp.mos.waitsemacount, 1)
+	ret := thrwakeup(uintptr(unsafe.Pointer(&mp.mos.waitsemacount)), 1)
+	if ret != 0 && ret != _ESRCH {
+		// semawakeup can be called on signal stack.
+		systemstack(func() {
+			print("thrwakeup addr=", &mp.mos.waitsemacount, " sem=", mp.mos.waitsemacount, " ret=", ret, "\n")
+		})
+	}
+}