--- xnu/xnu-792.6.76/iokit/Kernel/IOWorkLoop.cpp
+++ xnu/xnu-201.14/iokit/Kernel/IOWorkLoop.cpp
@@ -57,6 +57,16 @@
 
 #define fFlags loopRestart
 
+void IOWorkLoop::launchThreadMain(void *self)
+{
+    register thread_t mythread = current_thread();
+
+    // Make sure that this thread always has a kernel stack
+    stack_privilege(mythread);
+    thread_set_cont_arg((int) self);
+    threadMainContinuation();
+}
+
 bool IOWorkLoop::init()
 {
     // The super init and gateLock allocation MUST be done first
@@ -84,7 +94,7 @@
     if (addEventSource(controlG) != kIOReturnSuccess)
         return false;
 
-    workThread = IOCreateThread((thread_continue_t)threadMainContinuation, this);
+    workThread = IOCreateThread(launchThreadMain, (void *) this);
     if (!workThread)
         return false;
 
@@ -97,7 +107,7 @@
     IOWorkLoop *me = new IOWorkLoop;
 
     if (me && !me->init()) {
-        me->release();
+        me->free();
         return 0;
     }
 
@@ -240,9 +250,12 @@
 
 #endif /* KDEBUG */
 
-void IOWorkLoop::threadMainContinuation(IOWorkLoop *self)
-{
-	self->threadMain();
+void IOWorkLoop::threadMainContinuation()
+{
+  IOWorkLoop* self;
+  self = (IOWorkLoop *) thread_get_cont_arg();
+
+  self->threadMain();
 }
 
 void IOWorkLoop::threadMain()
@@ -285,7 +298,13 @@
 	    assert_wait((void *) &workToDo, false);
 	    IOSimpleLockUnlockEnableInterrupt(workToDoLock, is);
 
-	    thread_block_parameter((thread_continue_t)threadMainContinuation, this);
+#if defined (__i386__)
+	    thread_block(0);
+	    continue;
+#else
+	    thread_set_cont_arg((int) this);
+	    thread_block(&threadMainContinuation);
+#endif
 	    /* NOTREACHED */
 	}
 
@@ -302,7 +321,7 @@
 exitThread:
     workThread = 0;	// Say we don't have a loop and free ourselves
     free();
-    IOExitThread();
+    IOExitThread(0);
 }
 
 IOThread IOWorkLoop::getThread() const
@@ -357,8 +376,8 @@
 }
 
 IOReturn IOWorkLoop::runAction(Action inAction, OSObject *target,
-                                  void *arg0, void *arg1,
-                                  void *arg2, void *arg3)
+                                  void *arg0 = 0, void *arg1 = 0,
+                                  void *arg2 = 0, void *arg3 = 0)
 {
     IOReturn res;
 
@@ -379,48 +398,43 @@
     switch (command)
     {
     case mAddEvent:
-        if (!inEvent->getWorkLoop()) {
-            SETP(&fFlags, kLoopRestart);
-
-            inEvent->retain();
-            inEvent->setWorkLoop(this);
-            inEvent->setNext(0);
-    
-            if (!eventChain)
-                eventChain = inEvent;
-            else {
-                IOEventSource *event, *next;
-    
-                for (event = eventChain; (next = event->getNext()); event = next)
-                    ;
-                event->setNext(inEvent);
-            }
+	SETP(&fFlags, kLoopRestart);
+        inEvent->retain();
+        inEvent->setWorkLoop(this);
+        inEvent->setNext(0);
+
+        if (!eventChain)
+            eventChain = inEvent;
+        else {
+            IOEventSource *event, *next;
+
+            for (event = eventChain; (next = event->getNext()); event = next)
+                ;
+            event->setNext(inEvent);
         }
         break;
 
     case mRemoveEvent:
-        if (inEvent->getWorkLoop()) {
-            if (eventChain == inEvent)
-                eventChain = inEvent->getNext();
-            else {
-                IOEventSource *event, *next;
-    
-                event = eventChain;
-                while ((next = event->getNext()) && next != inEvent)
-                    event = next;
-    
-                if (!next) {
-                    res = kIOReturnBadArgument;
-                    break;
-                }
-                event->setNext(inEvent->getNext());
+        if (eventChain == inEvent)
+            eventChain = inEvent->getNext();
+        else {
+            IOEventSource *event, *next;
+
+            event = eventChain;
+            while ((next = event->getNext()) && next != inEvent)
+                event = next;
+
+            if (!next) {
+                res = kIOReturnBadArgument;
+                break;
             }
-    
-            inEvent->setWorkLoop(0);
-            inEvent->setNext(0);
-            inEvent->release();
-            SETP(&fFlags, kLoopRestart);
+            event->setNext(inEvent->getNext());
         }
+
+        inEvent->setWorkLoop(0);
+        inEvent->setNext(0);
+        inEvent->release();
+	SETP(&fFlags, kLoopRestart);
         break;
 
     default: