@Override
      public Class<?> loadClass(String name) throws ClassNotFoundException {
        if (disallowedClassNames.contains(name)) {
          throw new ClassNotFoundException("I'm sorry Dave, I'm afraid I can't do that.");
        }
        if (name.startsWith(concurrentPackage)) {
          Class<?> c = findLoadedClass(name);
          if (c == null) {
            return super.findClass(name);
          }

	}

	// Fast path: drop lock bit.
	new := atomic.AddInt32(&m.state, -mutexLocked)
	if new != 0 {
		// Outlined slow path to allow inlining the fast path.
		// To hide unlockSlow during tracing we skip one extra frame when tracing GoUnblock.
		m.unlockSlow(new)
	}
}

func (m *Mutex) unlockSlow(new int32) {
	if (new+mutexLocked)&mutexLocked == 0 {
		fatal("sync: unlock of unlocked mutex")
	}

      @Override
      public Class<?> loadClass(String name) throws ClassNotFoundException {
        if (disallowedClassNames.contains(name)) {
          throw new ClassNotFoundException("I'm sorry Dave, I'm afraid I can't do that.");
        }
        if (name.startsWith(concurrentPackage)) {
          Class<?> c = findLoadedClass(name);
          if (c == null) {
            return super.findClass(name);
          }

	MOVD	m_g0(R7), R10		// g0 for m
	CMP	R10, g			// same g0?
	BEQ	call			// already on g0
	MOVD	(g_sched+gobuf_sp)(R10), R1 // switch R1
call:
	// prepare frame for C ABI
	SUB	$32, R1			// create frame for callee saving LR, CR, R2 etc.
	RLDCR   $0, R1, $~15, R1	// align SP to 16 bytes
	MOVD	R8, CTR			// R8 = caller addr
	MOVD	R8, R12			// expected by PPC64 ABI
	BL	(CTR)

}

// A ScopeID represents a lexical scope within a function.
type ScopeID int32

const (
	funcDupok      = 1 << iota // duplicate definitions ok
	funcWrapper                // hide frame from users (elide in tracebacks, don't count as a frame for recover())
	funcABIWrapper             // is an ABI wrapper (also set flagWrapper)
	funcNeedctxt               // function uses context register (has closure variables)

	MOVD	24(R1), R2

	UNSTACK_AND_RESTORE_GO_TO_HOST_ABI(32)
	RET

#ifdef GOARCH_ppc64le
TEXT runtime·cgoSigtramp(SB),NOSPLIT|NOFRAME,$0
	// The stack unwinder, presumably written in C, may not be able to
	// handle Go frame correctly. So, this function is NOFRAME, and we
	// save/restore LR manually, and obey ELFv2 calling conventions.
	MOVD	LR, R10

	// We're coming from C code, initialize R0
	MOVD	$0, R0

	op := operands[next]
	if len(op) < 2 || op[0].ScanToken != '$' {
		p.errorf("TEXT %s: frame size must be an immediate constant", name)
		return
	}
	op = op[1:]
	negative := false
	if op[0].ScanToken == '-' {
		negative = true
		op = op[1:]
	}
	if len(op) == 0 || op[0].ScanToken != scanner.Int {
		p.errorf("TEXT %s: frame size must be an immediate constant", name)
		return
	}

	// 3. By debugCallWrap to pass parameters to a new goroutine because allocating a
	//    closure in the runtime is forbidden.
	// 4. When a panic is recovered and control returns to the respective frame,
	//    param may point to a savedOpenDeferState.
	param        unsafe.Pointer
	atomicstatus atomic.Uint32
	stackLock    uint32 // sigprof/scang lock; TODO: fold in to atomicstatus
	goid         uint64

	re(`-fmacro-backtrace-limit=(.+)`),
	re(`-fmessage-length=(.+)`),
	re(`-f(no-)?modules`),
	re(`-f(no-)?objc-arc`),
	re(`-f(no-)?objc-nonfragile-abi`),
	re(`-f(no-)?objc-legacy-dispatch`),
	re(`-f(no-)?omit-frame-pointer`),
	re(`-f(no-)?openmp(-simd)?`),
	re(`-f(no-)?permissive`),
	re(`-f(no-)?(pic|PIC|pie|PIE)`),
	re(`-f(no-)?plt`),
	re(`-f(no-)?rtti`),
	re(`-f(no-)?split-stack`),
	re(`-f(no-)?stack-(.+)`),

	i := 0
	stk.Frames(func(f trace.StackFrame) bool {
		if i == 0 {
			// Allow for one fully zero stack.
			//
			// TODO(mknyszek): Investigate why that happens.
			return true
		}
		if f.Func == "" || f.File == "" || f.PC == 0 || f.Line == 0 {
			e.Errorf("invalid stack frame %#v: missing information", f)
		}
		i++
		return true
	})
}