runtime: correct semaphore implementation on netbsd

NetBSD's semaphores use the underlying lighweight process mechanism
(LWP) on NetBSD, rather than pthreads. This means the m.prodcid needs
to be set to the LWP ID rather than the pthread ID in order for unpark
notifications to get sent to the right place.

Introduce a new getProcID() method that selects the correct ID for the
platform.

Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/261742

6 files changed, 29 insertions, 7 deletions

diff --git a/libgo/go/runtime/os_aix.go b/libgo/go/runtime/os_aix.go
index 951aeb6..f49b83c 100644
--- a/libgo/go/runtime/os_aix.go
+++ b/libgo/go/runtime/os_aix.go
@@ -21,6 +21,10 @@ type mOS struct {
 	waitsema uintptr // semaphore for parking on locks
 }
 
+func getProcID() uint64 {
+	return uint64(gettid())
+}
+
 //extern malloc
 func libc_malloc(uintptr) unsafe.Pointer
 
diff --git a/libgo/go/runtime/os_gccgo.go b/libgo/go/runtime/os_gccgo.go
index ab19022..a8859c0 100644
--- a/libgo/go/runtime/os_gccgo.go
+++ b/libgo/go/runtime/os_gccgo.go
@@ -27,8 +27,7 @@ func mpreinit(mp *m) {
 func minit() {
 	minitSignals()
 
-	// FIXME: only works on linux for now.
-	getg().m.procid = uint64(gettid())
+	getg().m.procid = getProcID()
 }
 
 // Called from dropm to undo the effect of an minit.
diff --git a/libgo/go/runtime/os_hurd.go b/libgo/go/runtime/os_hurd.go
index b3c6f80..1613b41 100644
--- a/libgo/go/runtime/os_hurd.go
+++ b/libgo/go/runtime/os_hurd.go
@@ -18,6 +18,10 @@ type mOS struct {
 	waitsema uintptr // semaphore for parking on locks
 }
 
+func getProcID() uint64 {
+	return uint64(gettid())
+}
+
 //extern malloc
 func libc_malloc(uintptr) unsafe.Pointer
 
diff --git a/libgo/go/runtime/os_linux.go b/libgo/go/runtime/os_linux.go
index 5d55064..627b6d6 100644
--- a/libgo/go/runtime/os_linux.go
+++ b/libgo/go/runtime/os_linux.go
@@ -13,6 +13,10 @@ type mOS struct {
 	unused byte
 }
 
+func getProcID() uint64 {
+	return uint64(gettid())
+}
+
 func futex(addr unsafe.Pointer, op int32, val uint32, ts, addr2 unsafe.Pointer, val3 uint32) int32 {
 	return int32(syscall(_SYS_futex, uintptr(addr), uintptr(op), uintptr(val), uintptr(ts), uintptr(addr2), uintptr(val3)))
 }
diff --git a/libgo/go/runtime/os_netbsd.go b/libgo/go/runtime/os_netbsd.go
index 69d2c71..89a8d07 100644
--- a/libgo/go/runtime/os_netbsd.go
+++ b/libgo/go/runtime/os_netbsd.go
@@ -14,12 +14,19 @@ type mOS struct {
 	waitsemacount uint32
 }
 
+func getProcID() uint64 {
+	return uint64(lwp_self())
+}
+
+//extern _lwp_self
+func lwp_self() int32
+
 //go:noescape
-//extern lwp_park
+//extern _lwp_park
 func lwp_park(ts int32, rel int32, abstime *timespec, unpark int32, hint, unparkhint unsafe.Pointer) int32
 
 //go:noescape
-//extern lwp_unpark
+//extern _lwp_unpark
 func lwp_unpark(lwp int32, hint unsafe.Pointer) int32
 
 //go:noescape
@@ -88,7 +95,7 @@ func semasleep(ns int64) int32 {
 			tsp = &ts
 		}
 		ret := lwp_park(_CLOCK_MONOTONIC, _TIMER_RELTIME, tsp, 0, unsafe.Pointer(&_g_.m.waitsemacount), nil)
-		if ret == _ETIMEDOUT {
+		if ret != 0 && errno() == _ETIMEDOUT {
 			return -1
 		}
 	}
@@ -101,10 +108,10 @@ func semawakeup(mp *m) {
 	// "If the target LWP is not currently waiting, it will return
 	// immediately upon the next call to _lwp_park()."
 	ret := lwp_unpark(int32(mp.procid), unsafe.Pointer(&mp.waitsemacount))
-	if ret != 0 && ret != _ESRCH {
+	if ret != 0 && errno() != _ESRCH {
 		// semawakeup can be called on signal stack.
 		systemstack(func() {
-			print("thrwakeup addr=", &mp.waitsemacount, " sem=", mp.waitsemacount, " ret=", ret, "\n")
+			print("thrwakeup addr=", &mp.waitsemacount, " sem=", mp.waitsemacount, " errno=", errno(), "\n")
 		})
 	}
 }
diff --git a/libgo/go/runtime/os_solaris.go b/libgo/go/runtime/os_solaris.go
index 63b5cd7..c568629 100644
--- a/libgo/go/runtime/os_solaris.go
+++ b/libgo/go/runtime/os_solaris.go
@@ -10,6 +10,10 @@ type mOS struct {
 	waitsema uintptr // semaphore for parking on locks
 }
 
+func getProcID() uint64 {
+	return uint64(gettid())
+}
+
 //extern malloc
 func libc_malloc(uintptr) unsafe.Pointer