if err != 0 {
		writeErrStr(failthreadcreate)
		exit(1)
	}

	// Find out OS stack size for our own stack guard.
	var stacksize uintptr
	if pthread_attr_getstacksize(&attr, &stacksize) != 0 {
		writeErrStr(failthreadcreate)
		exit(1)
	}
	mp.g0.stack.hi = stacksize // for mstart

	// Tell the pthread library we won't join with this thread.
	if pthread_attr_setdetachstate(&attr, _PTHREAD_CREATE_DETACHED) != 0 {

	// utilizing c-shared/c-archive force external linking.
	param := thrparam{
		start_func: uintptr(fn),
		arg:        nil,
		stack_base: uintptr(stack), //+stacksize?
		stack_size: stacksize,
		child_tid:  nil, // minit will record tid
		parent_tid: nil,
		tls_base:   unsafe.Pointer(&m0.tls[0]),
		tls_size:   unsafe.Sizeof(m0.tls),
	}

	var oset sigset

   *
   * <ul>
   *   <li>{@code getStackTrace} takes {@code stackSize} time to return but then negligible time to
   *       retrieve each element of the returned list.
   *   <li>{@code lazyStackTrace} takes negligible time to return but then {@code 1/stackSize} time
   *       to retrieve each element of the returned list (probably slightly more than {@code
   *       1/stackSize}).
   * </ul>
   *

   *
   * <ul>
   *   <li>{@code getStackTrace} takes {@code stackSize} time to return but then negligible time to
   *       retrieve each element of the returned list.
   *   <li>{@code lazyStackTrace} takes negligible time to return but then {@code 1/stackSize} time
   *       to retrieve each element of the returned list (probably slightly more than {@code
   *       1/stackSize}).
   * </ul>
   *

	}
}

// Version of newosproc that doesn't require a valid G.
//
//go:nosplit
func newosproc0(stacksize uintptr, fn unsafe.Pointer) {
	stack := sysAlloc(stacksize, &memstats.stacks_sys)
	if stack == nil {
		writeErrStr(failallocatestack)
		exit(1)
	}
	ret := clone(cloneFlags, unsafe.Pointer(uintptr(stack)+stacksize), nil, nil, fn)
	if ret < 0 {
		writeErrStr(failthreadcreate)
		exit(1)
	}
}

const (

// profilez samples are a repeated sequence of stack frames of the
// form:
//
//	1st word -- The number of times this stack was encountered.
//	2nd word -- The size of the stack (StackSize).
//	3rd word -- The first address on the stack.
//	...
//	StackSize + 2 -- The last address on the stack
//
// The last stack trace is of the form:
//
//	1st word -- 0
//	2nd word -- 1
//	3rd word -- 0
//

	MOVQ	0(DI), DI		// arg 1 - attr
	CALL	libc_pthread_attr_destroy(SB)
	RET

TEXT runtime·pthread_attr_getstacksize_trampoline(SB),NOSPLIT,$0
	MOVQ	8(DI), SI		// arg 2 - stacksize
	MOVQ	0(DI), DI		// arg 1 - attr
	CALL	libc_pthread_attr_getstacksize(SB)
	RET

TEXT runtime·pthread_attr_setdetachstate_trampoline(SB),NOSPLIT,$0
	MOVQ	8(DI), SI		// arg 2 - detachstate

	parentTID  uint64 // Where to store child TID, in parent's memory (pid_t *)
	exitSignal uint64 // Signal to deliver to parent on child termination
	stack      uint64 // Pointer to lowest byte of stack
	stackSize  uint64 // Size of stack
	tls        uint64 // Location of new TLS
	setTID     uint64 // Pointer to a pid_t array (since Linux 5.5)
	setTIDSize uint64 // Number of elements in set_tid (since Linux 5.5)

	g.init(int32(gcPercent), memoryLimit)
	return g
}

func (c *GCController) StartCycle(stackSize, globalsSize uint64, scannableFrac float64, gomaxprocs int) {
	trigger, _ := c.trigger()
	if c.heapMarked > trigger {
		trigger = c.heapMarked
	}
	c.maxStackScan.Store(stackSize)
	c.globalsScan.Store(globalsSize)
	c.heapLive.Store(trigger)

	MOVD	_cgo_sys_thread_create(SB), R1
	CMP	R1, $0
	BEQ	nocgo
	MOVD	$_rt0_s390x_lib_go(SB), R2
	MOVD	$0, R3
	BL	R1
	BR	restore

nocgo:
	MOVD	$0x800000, R1              // stacksize
	MOVD	R1, 0(R15)
	MOVD	$_rt0_s390x_lib_go(SB), R1
	MOVD	R1, 8(R15)                 // fn
	MOVD	$runtime·newosproc(SB), R1
	BL	R1

restore:
	// Restore F8-F15 from our stack frame.
	FMOVD	16(R15), F8