if gp.lockedm == 0 {
		return nil, plainError("goroutine not locked to thread")
	}

	tid := int(gp.lockedm.ptr().procid)
	if tid == 0 {
		return nil, plainError("missing tid")
	}

	f := efaceOf(&fn)
	if f._type == nil || f._type.Kind_&abi.KindMask != abi.Func {
		return nil, plainError("fn must be a function")
	}
	fv := (*funcval)(f.data)

	a := efaceOf(&stackArgs)

func (e errorAddressString) Addr() uintptr {
	return e.addr
}

// plainError represents a runtime error described a string without
// the prefix "runtime error: " after invoking errorString.Error().
// See Issue #14965.
type plainError string

func (e plainError) RuntimeError() {}

func (e plainError) Error() string {
	return string(e)
}

	typeBitsBulkBarrier(t, uintptr(dst), uintptr(src), t.Size_)
	memmove(dst, src, t.Size_)
}

func closechan(c *hchan) {
	if c == nil {
		panic(plainError("close of nil channel"))
	}

	lock(&c.lock)
	if c.closed != 0 {
		unlock(&c.lock)
		panic(plainError("close of closed channel"))
	}

	if raceenabled {
		callerpc := getcallerpc()
		racewritepc(c.raceaddr(), callerpc, abi.FuncPCABIInternal(closechan))

//
// Do not remove or change the type signature.
// See go.dev/issue/67401.
//
//go:linkname mapassign_fast64
func mapassign_fast64(t *maptype, h *hmap, key uint64) unsafe.Pointer {
	if h == nil {
		panic(plainError("assignment to entry in nil map"))
	}
	if raceenabled {
		callerpc := getcallerpc()
		racewritepc(unsafe.Pointer(h), callerpc, abi.FuncPCABIInternal(mapassign_fast64))
	}
	if h.flags&hashWriting != 0 {

//
// Do not remove or change the type signature.
// See go.dev/issue/67401.
//
//go:linkname mapassign_fast32
func mapassign_fast32(t *maptype, h *hmap, key uint32) unsafe.Pointer {
	if h == nil {
		panic(plainError("assignment to entry in nil map"))
	}
	if raceenabled {
		callerpc := getcallerpc()
		racewritepc(unsafe.Pointer(h), callerpc, abi.FuncPCABIInternal(mapassign_fast32))
	}
	if h.flags&hashWriting != 0 {

//
// Do not remove or change the type signature.
// See go.dev/issue/67401.
//
//go:linkname mapassign_faststr
func mapassign_faststr(t *maptype, h *hmap, s string) unsafe.Pointer {
	if h == nil {
		panic(plainError("assignment to entry in nil map"))
	}
	if raceenabled {
		callerpc := getcallerpc()
		racewritepc(unsafe.Pointer(h), callerpc, abi.FuncPCABIInternal(mapassign_faststr))
	}
	if h.flags&hashWriting != 0 {

func userArenaHeapBitsSetSliceType(typ *_type, n int, ptr unsafe.Pointer, s *mspan) {
	mem, overflow := math.MulUintptr(typ.Size_, uintptr(n))
	if overflow || n < 0 || mem > maxAlloc {
		panic(plainError("runtime: allocation size out of range"))
	}
	for i := 0; i < n; i++ {
		userArenaHeapBitsSetType(typ, add(ptr, uintptr(i)*typ.Size_), s)
	}
}

func newarray(typ *_type, n int) unsafe.Pointer {
	if n == 1 {
		return mallocgc(typ.Size_, typ, true)
	}
	mem, overflow := math.MulUintptr(typ.Size_, uintptr(n))
	if overflow || mem > maxAlloc || n < 0 {
		panic(plainError("runtime: allocation size out of range"))
	}
	return mallocgc(mem, typ, true)
}

// reflect_unsafe_NewArray is meant for package reflect,
// but widely used packages access it using linkname.

//
// Do not remove or change the type signature.
// See go.dev/issue/67401.
//
//go:linkname mapassign
func mapassign(t *maptype, h *hmap, key unsafe.Pointer) unsafe.Pointer {
	if h == nil {
		panic(plainError("assignment to entry in nil map"))
	}
	if raceenabled {
		callerpc := getcallerpc()
		pc := abi.FuncPCABIInternal(mapassign)
		racewritepc(unsafe.Pointer(h), callerpc, pc)

func badmcall(fn func(*g)) {
	throw("runtime: mcall called on m->g0 stack")
}

func badmcall2(fn func(*g)) {
	throw("runtime: mcall function returned")
}

func badreflectcall() {
	panic(plainError("arg size to reflect.call more than 1GB"))
}

//go:nosplit
//go:nowritebarrierrec
func badmorestackg0() {
	if !crashStackImplemented {
		writeErrStr("fatal: morestack on g0\n")
		return
	}