diff --git a/src/runtime/os_plan9.go b/src/runtime/os_plan9.go
index 679bf34519..870404b948 100644
--- a/src/runtime/os_plan9.go
+++ b/src/runtime/os_plan9.go
@@ -6,6 +6,11 @@ package runtime
 
 import "unsafe"
 
+func close(fd int32) int32
+
+//go:noescape
+func open(name *byte, mode, perm int32) int32
+
 //go:noescape
 func pread(fd int32, buf unsafe.Pointer, nbytes int32, offset int64) int32
 
diff --git a/src/runtime/proc.go b/src/runtime/proc.go
index 0411d965a4..027416a9ec 100644
--- a/src/runtime/proc.go
+++ b/src/runtime/proc.go
@@ -32,7 +32,9 @@ func main() {
 		maxstacksize = 250000000
 	}
 
-	systemstack(newsysmon)
+	systemstack(func() {
+		newm(sysmon, nil)
+	})
 
 	// Lock the main goroutine onto this, the main OS thread,
 	// during initialization.  Most programs won't care, but a few
diff --git a/src/runtime/proc1.go b/src/runtime/proc1.go
index 1f3ae500fc..471ffc83a3 100644
--- a/src/runtime/proc1.go
+++ b/src/runtime/proc1.go
@@ -81,10 +81,6 @@ func schedinit() {
 	}
 }
 
-func newsysmon() {
-	_newm(sysmon, nil)
-}
-
 func dumpgstatus(gp *g) {
 	_g_ := getg()
 	print("runtime: gp: gp=", gp, ", goid=", gp.goid, ", gp->atomicstatus=", readgstatus(gp), "\n")
@@ -638,7 +634,7 @@ func starttheworld() {
 			notewakeup(&mp.park)
 		} else {
 			// Start M to run P.  Do not start another M below.
-			_newm(nil, p)
+			newm(nil, p)
 			add = false
 		}
 	}
@@ -658,7 +654,7 @@ func starttheworld() {
 		// coordinate.  This lazy approach works out in practice:
 		// we don't mind if the first couple gc rounds don't have quite
 		// the maximum number of procs.
-		_newm(mhelpgc, nil)
+		newm(mhelpgc, nil)
 	}
 	_g_.m.locks--
 	if _g_.m.locks == 0 && _g_.preempt { // restore the preemption request in case we've cleared it in newstack
@@ -960,7 +956,7 @@ func unlockextra(mp *m) {
 }
 
 // Create a new m.  It will start off with a call to fn, or else the scheduler.
-func _newm(fn func(), _p_ *p) {
+func newm(fn func(), _p_ *p) {
 	mp := allocm(_p_)
 	mp.nextp = _p_
 	mp.mstartfn = *(*unsafe.Pointer)(unsafe.Pointer(&fn))
@@ -1037,7 +1033,7 @@ func startm(_p_ *p, spinning bool) {
 		if spinning {
 			fn = mspinning
 		}
-		_newm(fn, _p_)
+		newm(fn, _p_)
 		return
 	}
 	if mp.spinning {
@@ -2667,7 +2663,7 @@ func checkdead() {
 		}
 		mp := mget()
 		if mp == nil {
-			_newm(nil, _p_)
+			newm(nil, _p_)
 		} else {
 			mp.nextp = _p_
 			notewakeup(&mp.park)
diff --git a/src/runtime/stubs3.go b/src/runtime/stubs3.go
deleted file mode 100644
index ffaa28775d..0000000000
--- a/src/runtime/stubs3.go
+++ /dev/null
@@ -1,12 +0,0 @@
-// Copyright 2014 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.
-
-// +build plan9
-
-package runtime
-
-func close(fd int32) int32
-
-//go:noescape
-func open(name *byte, mode, perm int32) int32