// other (nosplit) call before this call (including the call to lock() itself).
//
// However, we switch to the systemstack to record the lock held to ensure that
// we record an accurate lock ordering. e.g., without systemstack, a stack
// split on entry to lock2() would record stack split locks as taken after l,
// even though l is not actually locked yet.
func lockWithRank(l *mutex, rank lockRank) {

func mcall(fn func(*g))

// systemstack runs fn on a system stack.
// If systemstack is called from the per-OS-thread (g0) stack, or
// if systemstack is called from the signal handling (gsignal) stack,
// systemstack calls fn directly and returns.
// Otherwise, systemstack is being called from the limited stack
// of an ordinary goroutine. In this case, systemstack switches

	if pin {
		if pinState.isPinned() {
			// multiple pins on same object, set multipin bit
			pinState.setMultiPinned(true)
			// and increase the pin counter
			// TODO(mknyszek): investigate if systemstack is necessary here
			systemstack(func() {
				offset := objIndex * span.elemsize
				span.incPinCounter(offset)
			})
		} else {
			// set pin bit
			pinState.setPinned(true)
		}
	} else {
		// unpin

	return (*LFNode)((*lfstack)(head).pop())
}
func LFNodeValidate(node *LFNode) {
	lfnodeValidate((*lfnode)(unsafe.Pointer(node)))
}

func Netpoll(delta int64) {
	systemstack(func() {
		netpoll(delta)
	})
}

func GCMask(x any) (ret []byte) {
	systemstack(func() {
		ret = getgcmask(x)
	})
	return
}

func RunSchedLocalQueueTest() {
	pp := new(p)
	gs := make([]g, len(pp.runq))

// thus the code is largely similar. See Linux implementation
// and lock_futex.go for comments.

//go:nosplit
func futexsleep(addr *uint32, val uint32, ns int64) {
	systemstack(func() {
		futexsleep1(addr, val, ns)
	})
}

func futexsleep1(addr *uint32, val uint32, ns int64) {
	var utp *umtx_time
	if ns >= 0 {
		var ut umtx_time
		ut._clockid = _CLOCK_MONOTONIC

	case _WAIT_TIMEOUT:
		return -1

	case _WAIT_ABANDONED:
		systemstack(func() {
			throw("runtime.semasleep wait_abandoned")
		})

	case _WAIT_FAILED:
		systemstack(func() {
			print("runtime: waitforsingleobject wait_failed; errno=", getlasterror(), "\n")
			throw("runtime.semasleep wait_failed")
		})

	default:
		systemstack(func() {

// It's important that any use of gcWork during the mark phase prevent
// the garbage collector from transitioning to mark termination since
// gcWork may locally hold GC work buffers. This can be done by
// disabling preemption (systemstack or acquirem).
type gcWork struct {
	// wbuf1 and wbuf2 are the primary and secondary work buffers.
	//
	// This can be thought of as a stack of both work buffers'
	// pointers concatenated. When we pop the last pointer, we

	}
}

func TestTracebackSystemstack(t *testing.T) {
	if GOARCH == "ppc64" || GOARCH == "ppc64le" {
		t.Skip("systemstack tail call not implemented on ppc64x")
	}

	// Test that profiles correctly jump over systemstack,
	// including nested systemstack calls.
	pcs := make([]uintptr, 20)
	pcs = pcs[:TracebackSystemstack(pcs, 5)]
	// Check that runtime.TracebackSystemstack appears five times

	// switch to g0
	MOVD R2, g

	// call fn
	Get CTXT
	I32WrapI64
	I64Load $0
	CALL

	Get SP
	I32Const $8
	I32Add
	Set SP

	JMP runtime·badmcall2(SB)

// func systemstack(fn func())
TEXT runtime·systemstack(SB), NOSPLIT, $0-8
	// R0 = fn
	MOVD fn+0(FP), R0
	// R1 = g.m
	MOVD g_m(g), R1
	// R2 = g0
	MOVD m_g0(R1), R2

	// if g == g0
	Get g
	Get R2

	size uintptr   // total size of stacks in list
}

// dummy mspan that contains no free objects.
var emptymspan mspan

func allocmcache() *mcache {
	var c *mcache
	systemstack(func() {
		lock(&mheap_.lock)
		c = (*mcache)(mheap_.cachealloc.alloc())
		c.flushGen.Store(mheap_.sweepgen)
		unlock(&mheap_.lock)
	})
	for i := range c.alloc {
		c.alloc[i] = &emptymspan
	}