--- xnu/xnu-1228/iokit/Kernel/IOLocks.cpp
+++ xnu/xnu-3248.50.21/iokit/Kernel/IOLocks.cpp
@@ -25,15 +25,6 @@
  * 
  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  */
-/*
- * Copyright (c) 1998 Apple Computer, Inc.  All rights reserved. 
- *
- * HISTORY
- *
- */
-
-
-#define	IOLOCKS_CPP	1
 
 #include <IOKit/system.h>
 
@@ -46,6 +37,11 @@
 extern "C" {
 #include <kern/locks.h>
 
+#if defined(__x86_64__)
+/* Synthetic event if none is specified, for backwards compatibility only. */
+static bool IOLockSleep_NO_EVENT __attribute__((used)) = 0;
+#endif
+
 void	IOLockInitWithState( IOLock * lock, IOLockState state)
 {
     if( state == kIOLockStateLocked)
@@ -69,13 +65,13 @@
 
 int	IOLockSleep( IOLock * lock, void *event, UInt32 interType)
 {
-    return (int) lck_mtx_sleep(lock, LCK_SLEEP_DEFAULT, (event_t) event, (wait_interrupt_t) interType);
+    return (int) lck_mtx_sleep(lock, LCK_SLEEP_PROMOTED_PRI, (event_t) event, (wait_interrupt_t) interType);
 }
 
 int	IOLockSleepDeadline( IOLock * lock, void *event,
                                 AbsoluteTime deadline, UInt32 interType)
 {
-    return (int) lck_mtx_sleep_deadline(lock, LCK_SLEEP_DEFAULT, (event_t) event,
+    return (int) lck_mtx_sleep_deadline(lock, LCK_SLEEP_PROMOTED_PRI, (event_t) event,
     					(wait_interrupt_t) interType, __OSAbsoluteTime(deadline));
 }
 
@@ -83,6 +79,42 @@
 {   
 	thread_wakeup_prim((event_t) event, oneThread, THREAD_AWAKENED);
 }   
+
+#if defined(__x86_64__)
+/*
+ * For backwards compatibility, kexts built against pre-Darwin 14 headers will bind at runtime to this function,
+ * which supports a NULL event,
+ */
+int	IOLockSleep_legacy_x86_64( IOLock * lock, void *event, UInt32 interType) __asm("_IOLockSleep");
+int	IOLockSleepDeadline_legacy_x86_64( IOLock * lock, void *event,
+					   AbsoluteTime deadline, UInt32 interType) __asm("_IOLockSleepDeadline");
+void	IOLockWakeup_legacy_x86_64(IOLock * lock, void *event, bool oneThread) __asm("_IOLockWakeup");
+
+int	IOLockSleep_legacy_x86_64( IOLock * lock, void *event, UInt32 interType)
+{
+    if (event == NULL)
+        event = (void *)&IOLockSleep_NO_EVENT;
+
+    return IOLockSleep(lock, event, interType);
+}
+
+int	IOLockSleepDeadline_legacy_x86_64( IOLock * lock, void *event,
+			     AbsoluteTime deadline, UInt32 interType)
+{
+    if (event == NULL)
+        event = (void *)&IOLockSleep_NO_EVENT;
+
+    return IOLockSleepDeadline(lock, event, deadline, interType);
+}
+
+void	IOLockWakeup_legacy_x86_64(IOLock * lock, void *event, bool oneThread)
+{   
+    if (event == NULL)
+        event = (void *)&IOLockSleep_NO_EVENT;
+
+    IOLockWakeup(lock, event, oneThread);
+}   
+#endif /* defined(__x86_64__) */
 
 
 struct _IORecursiveLock {
@@ -195,11 +227,10 @@
     int res;
 
     assert(lock->thread == IOThreadSelf());
-    assert(lock->count == 1 || interType == THREAD_UNINT);
     
     lock->count = 0;
     lock->thread = 0;
-    res = lck_mtx_sleep(lock->mutex, LCK_SLEEP_DEFAULT, (event_t) event, (wait_interrupt_t) interType);
+    res = lck_mtx_sleep(lock->mutex, LCK_SLEEP_PROMOTED_PRI, (event_t) event, (wait_interrupt_t) interType);
 
     // Must re-establish the recursive lock no matter why we woke up
     // otherwise we would potentially leave the return path corrupted.
@@ -210,6 +241,29 @@
     return res;
 }
 
+int	IORecursiveLockSleepDeadline( IORecursiveLock * _lock, void *event,
+                                  AbsoluteTime deadline, UInt32 interType)
+{
+    _IORecursiveLock * lock = (_IORecursiveLock *)_lock;
+    UInt32 count = lock->count;
+    int res;
+
+    assert(lock->thread == IOThreadSelf());
+    
+    lock->count = 0;
+    lock->thread = 0;
+    res = lck_mtx_sleep_deadline(lock->mutex, LCK_SLEEP_PROMOTED_PRI, (event_t) event, 
+								      (wait_interrupt_t) interType, __OSAbsoluteTime(deadline));
+
+    // Must re-establish the recursive lock no matter why we woke up
+    // otherwise we would potentially leave the return path corrupted.
+    assert(lock->thread == 0);
+    assert(lock->count == 0);
+    lock->thread = IOThreadSelf();
+    lock->count = count;
+    return res;
+}
+
 void IORecursiveLockWakeup(IORecursiveLock *, void *event, bool oneThread)
 {
     thread_wakeup_prim((event_t) event, oneThread, THREAD_AWAKENED);