// lives at the bottom of the G stack from the one that lives
// at the top of the system stack because the one at the top of
// the system stack terminates the stack walk (see topofstack()).
// The frame layout needs to match systemstack
// so that it can pretend to be systemstack_switch.
TEXT runtime·systemstack_switch(SB), NOSPLIT, $0-0
	UNDEF
	// Make sure this function is not leaf,