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iokit/Kernel/IONVRAM.cpp xnu-344.49 xnu-8019.41.5
--- xnu/xnu-344.49/iokit/Kernel/IONVRAM.cpp
+++ xnu/xnu-8019.41.5/iokit/Kernel/IONVRAM.cpp
@@ -1,17 +1,21 @@
 /*
- * Copyright (c) 1998-2000 Apple Computer, Inc. All rights reserved.
+ * Copyright (c) 1998-2006 Apple Computer, Inc. All rights reserved.
+ * Copyright (c) 2007-2012 Apple Inc. All rights reserved.
  *
- * @APPLE_LICENSE_HEADER_START@
- * 
- * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
- * 
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
+ *
  * This file contains Original Code and/or Modifications of Original Code
  * as defined in and that are subject to the Apple Public Source License
  * Version 2.0 (the 'License'). You may not use this file except in
- * compliance with the License. Please obtain a copy of the License at
- * http://www.opensource.apple.com/apsl/ and read it before using this
- * file.
- * 
+ * compliance with the License. The rights granted to you under the License
+ * may not be used to create, or enable the creation or redistribution of,
+ * unlawful or unlicensed copies of an Apple operating system, or to
+ * circumvent, violate, or enable the circumvention or violation of, any
+ * terms of an Apple operating system software license agreement.
+ *
+ * Please obtain a copy of the License at
+ * http://www.opensource.apple.com/apsl/ and read it before using this file.
+ *
  * The Original Code and all software distributed under the License are
  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
@@ -19,1552 +23,2894 @@
  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  * Please see the License for the specific language governing rights and
  * limitations under the License.
- * 
- * @APPLE_LICENSE_HEADER_END@
+ *
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  */
 
+#define IOKIT_ENABLE_SHARED_PTR
+
+#include <AssertMacros.h>
 #include <IOKit/IOLib.h>
 #include <IOKit/IONVRAM.h>
 #include <IOKit/IOPlatformExpert.h>
 #include <IOKit/IOUserClient.h>
 #include <IOKit/IOKitKeys.h>
+#include <IOKit/IOKitKeysPrivate.h>
+#include <IOKit/IOBSD.h>
+#include <kern/debug.h>
+#include <sys/csr.h>
 
 #define super IOService
 
 OSDefineMetaClassAndStructors(IODTNVRAM, IOService);
 
-bool IODTNVRAM::init(IORegistryEntry *old, const IORegistryPlane *plane)
-{
-  OSDictionary *dict;
-  
-  if (!super::init(old, plane)) return false;
-  
-  dict =  OSDictionary::withCapacity(1);
-  if (dict == 0) return false;
-  setPropertyTable(dict);
-  
-  _nvramImage = IONew(UInt8, kIODTNVRAMImageSize);
-  if (_nvramImage == 0) return false;
-  
-  _nvramPartitionOffsets = OSDictionary::withCapacity(1);
-  if (_nvramPartitionOffsets == 0) return false;
-  
-  _nvramPartitionLengths = OSDictionary::withCapacity(1);
-  if (_nvramPartitionLengths == 0) return false;
-  
-  _registryPropertiesKey = OSSymbol::withCStringNoCopy("aapl,pci");
-  if (_registryPropertiesKey == 0) return false;
-  
-  return true;
-}
-
-void IODTNVRAM::registerNVRAMController(IONVRAMController *nvram)
-{
-  char   partitionID[18];
-  UInt32 partitionOffset, partitionLength;
-  UInt32 freePartitionOffset, freePartitionSize;
-  UInt32 currentLength, currentOffset = 0;
-  OSNumber *partitionOffsetNumber, *partitionLengthNumber;
-  
-  if (_nvramController != 0) return;
-  
-  _nvramController = nvram;
-  
-  _nvramController->read(0, _nvramImage, kIODTNVRAMImageSize);
-  
-  // Find the offsets for the OF, XPRAM, NameRegistry and PanicInfo partitions.
-  _ofPartitionOffset = 0xFFFFFFFF;
-  _xpramPartitionOffset = 0xFFFFFFFF;
-  _nrPartitionOffset = 0xFFFFFFFF;
-  _piPartitionOffset = 0xFFFFFFFF;
-  freePartitionOffset = 0xFFFFFFFF;
-  freePartitionSize = 0;
-  if (getPlatform()->getBootROMType()) {
-    // Look through the partitions to find the OF, MacOS partitions.
-    while (currentOffset < kIODTNVRAMImageSize) {
-      currentLength = ((UInt16 *)(_nvramImage + currentOffset))[1] * 16;
-      
-      partitionOffset = currentOffset + 16;
-      partitionLength = currentLength - 16;
-      
-      if (strncmp((const char *)_nvramImage + currentOffset + 4,
-		  kIODTNVRAMOFPartitionName, 12) == 0) {
-	_ofPartitionOffset = partitionOffset;
-	_ofPartitionSize = partitionLength;
-      } else if (strncmp((const char *)_nvramImage + currentOffset + 4,
-			 kIODTNVRAMXPRAMPartitionName, 12) == 0) {
-	_xpramPartitionOffset = partitionOffset;
-	_xpramPartitionSize = kIODTNVRAMXPRAMSize;
-	_nrPartitionOffset = _xpramPartitionOffset + _xpramPartitionSize;
-	_nrPartitionSize = partitionLength - _xpramPartitionSize;
-      } else if (strncmp((const char *)_nvramImage + currentOffset + 4,
-			 kIODTNVRAMPanicInfoPartitonName, 12) == 0) {
-	_piPartitionOffset = partitionOffset;
-	_piPartitionSize = partitionLength;
-      } else if (strncmp((const char *)_nvramImage + currentOffset + 4,
-			 kIODTNVRAMFreePartitionName, 12) == 0) {
-	freePartitionOffset = currentOffset;
-	freePartitionSize = currentLength;
-      } else {
-	// Construct the partition ID from the signature and name.
-	sprintf(partitionID, "0x%02x,",
-		*(UInt8 *)(_nvramImage + currentOffset));
-	strncpy(partitionID + 5,
-		(const char *)(_nvramImage + currentOffset + 4), 12);
-	partitionID[17] = '\0';
-	
-	partitionOffsetNumber = OSNumber::withNumber(partitionOffset, 32);
-	partitionLengthNumber = OSNumber::withNumber(partitionLength, 32);
-	
-	// Save the partition offset and length
-	_nvramPartitionOffsets->setObject(partitionID, partitionOffsetNumber);
-	_nvramPartitionLengths->setObject(partitionID, partitionLengthNumber);
-	
-	partitionOffsetNumber->release();
-	partitionLengthNumber->release();
-      }
-      currentOffset += currentLength;
-    }
-  } else {
-    // Use the fixed address for old world machines.
-    _ofPartitionOffset    = 0x1800;
-    _ofPartitionSize      = 0x0800;
-    _xpramPartitionOffset = 0x1300;
-    _xpramPartitionSize   = 0x0100;
-    _nrPartitionOffset    = 0x1400;
-    _nrPartitionSize      = 0x0400;
-  }
-  
-  if (_ofPartitionOffset != 0xFFFFFFFF)
-    _ofImage    = _nvramImage + _ofPartitionOffset;
-  if (_xpramPartitionOffset != 0xFFFFFFFF)
-    _xpramImage = _nvramImage + _xpramPartitionOffset;
-  if (_nrPartitionOffset != 0xFFFFFFFF)
-    _nrImage    = _nvramImage + _nrPartitionOffset;
-  
-  if (_piPartitionOffset == 0xFFFFFFFF) {
-    if (freePartitionSize > 0x20) {
-      // Set the signature to 0xa1.
-      _nvramImage[freePartitionOffset] = 0xa1;
-      // Set the checksum to 0.
-      _nvramImage[freePartitionOffset + 1] = 0;
-      // Set the name for the Panic Info partition.
-      strncpy((char *)(_nvramImage + freePartitionOffset + 4),
-	      kIODTNVRAMPanicInfoPartitonName, 12);
-      
-      // Calculate the partition offset and size.
-      _piPartitionOffset = freePartitionOffset + 0x10;
-      _piPartitionSize = 0x800;
-      if (_piPartitionSize + 0x20 > freePartitionSize)
-	_piPartitionSize = freePartitionSize - 0x20;
-      
-      _piImage = _nvramImage + _piPartitionOffset;
-      
-      // Zero the new partition.
-      bzero(_piImage, _piPartitionSize);
-      
-      // Set the partition size.
-      *(UInt16 *)(_nvramImage + freePartitionOffset + 2) =
-	(_piPartitionSize / 0x10) + 1;
-      
-      // Set the partition checksum.
-      _nvramImage[freePartitionOffset + 1] =
-	calculatePartitionChecksum(_nvramImage + freePartitionOffset);
-      
-      // Calculate the free partition offset and size.
-      freePartitionOffset += _piPartitionSize + 0x10;
-      freePartitionSize -= _piPartitionSize + 0x10;
-      
-      // Set the signature to 0x7f.
-      _nvramImage[freePartitionOffset] = 0x7f;
-      // Set the checksum to 0.
-      _nvramImage[freePartitionOffset + 1] = 0;
-      // Set the name for the free partition.
-      strncpy((char *)(_nvramImage + freePartitionOffset + 4),
-	      kIODTNVRAMFreePartitionName, 12);
-      // Set the partition size.
-      *(UInt16 *)(_nvramImage + freePartitionOffset + 2) =
-	freePartitionSize / 0x10;
-      // Set the partition checksum.
-      _nvramImage[freePartitionOffset + 1] =
-	calculatePartitionChecksum(_nvramImage + freePartitionOffset);
-      
-      // Set the nvram image as dirty.
-      _nvramImageDirty = true;
-    }
-  } else {
-    _piImage = _nvramImage + _piPartitionOffset;
-  }
-  
-  initOFVariables();
-}
-
-void IODTNVRAM::sync(void)
-{
-  if (!_nvramImageDirty && !_ofImageDirty) return;
-  
-  // Don't try to sync OF Variables if the system has already paniced.
-  if (!_systemPaniced) syncOFVariables();
-  
-  _nvramController->write(0, _nvramImage, kIODTNVRAMImageSize);
-  _nvramController->sync();
-  
-  _nvramImageDirty = false;
-}
-
-bool IODTNVRAM::serializeProperties(OSSerialize *serialize) const
-{
-  bool                 result;
-  UInt32               variablePerm;
-  const OSSymbol       *key;
-  OSDictionary         *dict, *tmpDict = 0;
-  OSCollectionIterator *iter = 0;
-  
-  if (_ofDict == 0) return false;
-  
-  // Verify permissions.
-  result = IOUserClient::clientHasPrivilege(current_task(), kIOClientPrivilegeAdministrator);
-  if (result != kIOReturnSuccess) {
-    tmpDict = OSDictionary::withCapacity(1);
-    if (tmpDict == 0) return false;
-    
-    iter = OSCollectionIterator::withCollection(_ofDict);
-    if (iter == 0) return false;
-    
-    while (1) {
-      key = OSDynamicCast(OSSymbol, iter->getNextObject());
-      if (key == 0) break;
-      
-      variablePerm = getOFVariablePerm(key);
-      if (variablePerm != kOFVariablePermRootOnly) {
-	tmpDict->setObject(key, _ofDict->getObject(key));
-      }
-    }
-    dict = tmpDict;
-  } else {
-    dict = _ofDict;
-  }
-  
-  result = dict->serialize(serialize);
-  
-  if (tmpDict != 0) tmpDict->release();
-  if (iter != 0) iter->release();
-  
-  return result;
-}
-
-OSObject *IODTNVRAM::getProperty(const OSSymbol *aKey) const
-{
-  IOReturn result;
-  UInt32   variablePerm;
-  
-  if (_ofDict == 0) return 0;
-  
-  // Verify permissions.
-  result = IOUserClient::clientHasPrivilege(current_task(), "root");
-  if (result != kIOReturnSuccess) {
-    variablePerm = getOFVariablePerm(aKey);
-    if (variablePerm == kOFVariablePermRootOnly) return 0;
-  }
-  
-  return _ofDict->getObject(aKey);
-}
-
-OSObject *IODTNVRAM::getProperty(const char *aKey) const
-{
-  const OSSymbol *keySymbol;
-  OSObject *theObject = 0;
-  
-  keySymbol = OSSymbol::withCStringNoCopy(aKey);
-  if (keySymbol != 0) {
-    theObject = getProperty(keySymbol);
-    keySymbol->release();
-  }
-  
-  return theObject;
-}
-
-bool IODTNVRAM::setProperty(const OSSymbol *aKey, OSObject *anObject)
-{
-  bool     result;
-  UInt32   propType, propPerm;
-  OSString *tmpString;
-  OSObject *propObject = 0;
-  
-  if (_ofDict == 0) return false;
-  
-  // Verify permissions.
-  result = IOUserClient::clientHasPrivilege(current_task(), "root");
-  if (result != kIOReturnSuccess) {
-    propPerm = getOFVariablePerm(aKey);
-    if (propPerm != kOFVariablePermUserWrite) return false;
-  }
-  
-  // Don't allow creation of new properties on old world machines.
-  if (getPlatform()->getBootROMType() == 0) {
-    if (_ofDict->getObject(aKey) == 0) return false;
-  }
-  
-  // Don't allow change of 'aapl,panic-info'.
-  if (aKey->isEqualTo(kIODTNVRAMPanicInfoKey)) return false;
-  
-  // Make sure the object is of the correct type.
-  propType = getOFVariableType(aKey);
-  switch (propType) {
-  case kOFVariableTypeBoolean :
-    propObject = OSDynamicCast(OSBoolean, anObject);
-    break;
-    
-  case kOFVariableTypeNumber :
-    propObject = OSDynamicCast(OSNumber, anObject);
-    break;
-    
-  case kOFVariableTypeString :
-    propObject = OSDynamicCast(OSString, anObject);
-    break;
-    
-  case kOFVariableTypeData :
-    propObject = OSDynamicCast(OSData, anObject);
-    if (propObject == 0) {
-      tmpString = OSDynamicCast(OSString, anObject);
-      if (tmpString != 0) {
-	propObject = OSData::withBytes(tmpString->getCStringNoCopy(),
-				       tmpString->getLength());
-      }
-    }
-    break;
-  }
-  
-  if (propObject == 0) return false;
-  
-  result = _ofDict->setObject(aKey, propObject);
-  
-  if (result) {
-    if (getPlatform()->getBootROMType() == 0) {
-      updateOWBootArgs(aKey, propObject);
-    }
-    
-    _ofImageDirty = true;
-  }
-  
-  return result;
-}
-
-IOReturn IODTNVRAM::setProperties(OSObject *properties)
-{
-  bool                 result = true;
-  OSObject             *object;
-  const OSSymbol       *key;
-  OSDictionary         *dict;
-  OSCollectionIterator *iter;
-  
-  dict = OSDynamicCast(OSDictionary, properties);
-  if (dict == 0) return kIOReturnBadArgument;
-  
-  iter = OSCollectionIterator::withCollection(dict);
-  if (iter == 0) return kIOReturnBadArgument;
-  
-  while (result) {
-    key = OSDynamicCast(OSSymbol, iter->getNextObject());
-    if (key == 0) break;
-    
-    object = dict->getObject(key);
-    if (object == 0) continue;
-    
-    result = setProperty(key, object);
-  }
-  
-  iter->release();
-  
-  if (result) return kIOReturnSuccess;
-  else return kIOReturnError;
-}
-
-IOReturn IODTNVRAM::readXPRAM(IOByteCount offset, UInt8 *buffer,
-			      IOByteCount length)
-{
-  if (_xpramImage == 0) return kIOReturnUnsupported;
-  
-  if ((buffer == 0) || (length <= 0) || (offset < 0) ||
-      (offset + length > kIODTNVRAMXPRAMSize))
-    return kIOReturnBadArgument;
-  
-  bcopy(_nvramImage + _xpramPartitionOffset + offset, buffer, length);
-
-  return kIOReturnSuccess;
-}
-
-IOReturn IODTNVRAM::writeXPRAM(IOByteCount offset, UInt8 *buffer,
-			       IOByteCount length)
-{
-  if (_xpramImage == 0) return kIOReturnUnsupported;
-  
-  if ((buffer == 0) || (length <= 0) || (offset < 0) ||
-      (offset + length > kIODTNVRAMXPRAMSize))
-    return kIOReturnBadArgument;
-  
-  bcopy(buffer, _nvramImage + _xpramPartitionOffset + offset, length);
-
-  _nvramImageDirty = true;
-  
-  return kIOReturnSuccess;
-}
-
-IOReturn IODTNVRAM::readNVRAMProperty(IORegistryEntry *entry,
-				      const OSSymbol **name,
-				      OSData **value)
-{
-  IOReturn err;
-
-  if (getPlatform()->getBootROMType())
-    err = readNVRAMPropertyType1(entry, name, value);
-  else
-    err = readNVRAMPropertyType0(entry, name, value);
-  
-  return err;
-}
-
-IOReturn IODTNVRAM::writeNVRAMProperty(IORegistryEntry *entry,
-				       const OSSymbol *name,
-				       OSData *value)
-{
-  IOReturn err;
-  
-  if (getPlatform()->getBootROMType())
-    err = writeNVRAMPropertyType1(entry, name, value);
-  else
-    err = writeNVRAMPropertyType0(entry, name, value);
-  
-  return err;
-}
-
-OSDictionary *IODTNVRAM::getNVRAMPartitions(void)
-{
-  return _nvramPartitionLengths;
-}
-
-IOReturn IODTNVRAM::readNVRAMPartition(const OSSymbol *partitionID,
-				       IOByteCount offset, UInt8 *buffer,
-				       IOByteCount length)
-{
-  OSNumber *partitionOffsetNumber, *partitionLengthNumber;
-  UInt32   partitionOffset, partitionLength;
-  
-  partitionOffsetNumber =
-    (OSNumber *)_nvramPartitionOffsets->getObject(partitionID);
-  partitionLengthNumber =
-    (OSNumber *)_nvramPartitionLengths->getObject(partitionID);
-  
-  if ((partitionOffsetNumber == 0) || (partitionLengthNumber == 0))
-    return kIOReturnNotFound;
-  
-  partitionOffset = partitionOffsetNumber->unsigned32BitValue();
-  partitionLength = partitionLengthNumber->unsigned32BitValue();
-  
-  if ((buffer == 0) || (length <= 0) || (offset < 0) ||
-      (offset + length > partitionLength))
-    return kIOReturnBadArgument;
-  
-  bcopy(_nvramImage + partitionOffset + offset, buffer, length);
-  
-  return kIOReturnSuccess;
-}
-
-IOReturn IODTNVRAM::writeNVRAMPartition(const OSSymbol *partitionID,
-					IOByteCount offset, UInt8 *buffer,
-					IOByteCount length)
-{
-  OSNumber *partitionOffsetNumber, *partitionLengthNumber;
-  UInt32   partitionOffset, partitionLength;
-  
-  partitionOffsetNumber =
-    (OSNumber *)_nvramPartitionOffsets->getObject(partitionID);
-  partitionLengthNumber =
-    (OSNumber *)_nvramPartitionLengths->getObject(partitionID);
-  
-  if ((partitionOffsetNumber == 0) || (partitionLengthNumber == 0))
-    return kIOReturnNotFound;
-  
-  partitionOffset = partitionOffsetNumber->unsigned32BitValue();
-  partitionLength = partitionLengthNumber->unsigned32BitValue();
-  
-  if ((buffer == 0) || (length <= 0) || (offset < 0) ||
-      (offset + length > partitionLength))
-    return kIOReturnBadArgument;
-  
-  bcopy(buffer, _nvramImage + partitionOffset + offset, length);
-  
-  _nvramImageDirty = true;
-  
-  return kIOReturnSuccess;
-}
-
-UInt32 IODTNVRAM::savePanicInfo(UInt8 *buffer, IOByteCount length)
-{
-  if ((_piImage == 0) || (length <= 0)) return 0;
-  
-  if (length > (_piPartitionSize - 4))
-    length = _piPartitionSize - 4;
-  
-  // Save the Panic Info.
-  bcopy(buffer, _piImage + 4, length);
-  
-  // Save the Panic Info length.
-  *(UInt32 *)_piImage = length;
-  
-  _nvramImageDirty = true;
-  
-  _systemPaniced = true;
-  
-  return length;
+#define ARRAY_SIZE(x) (sizeof(x)/sizeof(x[0]))
+
+#define MAX_VAR_NAME_SIZE     63
+
+#define kCurrentGenerationCountKey "Generation"
+#define kCurrentNVRAMVersionKey    "Version"
+
+#define NVRAM_CHRP_APPLE_HEADER_NAME_V1  "nvram"
+#define NVRAM_CHRP_APPLE_HEADER_NAME_V2  "2nvram"
+
+#define NVRAM_CHRP_PARTITION_NAME_COMMON_V1   "common"
+#define NVRAM_CHRP_PARTITION_NAME_SYSTEM_V1   "system"
+#define NVRAM_CHRP_PARTITION_NAME_COMMON_V2   "2common"
+#define NVRAM_CHRP_PARTITION_NAME_SYSTEM_V2   "2system"
+
+#define NVRAM_CHRP_LENGTH_BLOCK_SIZE 0x10 // CHRP length field is in 16 byte blocks
+
+typedef struct chrp_nvram_header { //16 bytes
+	uint8_t  sig;
+	uint8_t  cksum; // checksum on sig, len, and name
+	uint16_t len;   // total length of the partition in 16 byte blocks starting with the signature
+	// and ending with the last byte of data area, ie len includes its own header size
+	char     name[12];
+	uint8_t  data[0];
+} chrp_nvram_header_t;
+
+typedef struct apple_nvram_header {  // 16 + 16 bytes
+	struct   chrp_nvram_header chrp;
+	uint32_t adler;
+	uint32_t generation;
+	uint8_t  padding[8];
+} apple_nvram_header_t;
+
+#define kIONVRAMPrivilege       kIOClientPrivilegeAdministrator
+
+#define MIN_SYNC_NOW_INTERVAL 15*60 /* Minimum 15 Minutes interval mandated */
+
+#if defined(DEBUG) || defined(DEVELOPMENT)
+#define DEBUG_INFO(fmt, args...)                                    \
+({                                                                  \
+	if (gNVRAMLogging)                                              \
+	IOLog("IONVRAM::%s:%u - " fmt, __FUNCTION__, __LINE__, ##args); \
+})
+
+#define DEBUG_ALWAYS(fmt, args...)                                  \
+({                                                                  \
+	IOLog("IONVRAM::%s:%u - " fmt, __FUNCTION__, __LINE__, ##args); \
+})
+#else
+#define DEBUG_INFO(fmt, args...) (void)NULL
+#define DEBUG_ALWAYS(fmt, args...) (void)NULL
+#endif
+
+#define DEBUG_ERROR DEBUG_ALWAYS
+
+#define SAFE_TO_LOCK() (preemption_enabled() && !panic_active())
+
+#define CONTROLLERLOCK()                 \
+({                                       \
+	if (SAFE_TO_LOCK())                  \
+	        IOLockLock(_controllerLock); \
+})
+
+#define CONTROLLERUNLOCK()                 \
+({                                         \
+	if (SAFE_TO_LOCK())                    \
+	        IOLockUnlock(_controllerLock); \
+})
+
+#define NVRAMREADLOCK()                   \
+({                                        \
+	if (SAFE_TO_LOCK())                   \
+	        IORWLockRead(_variableLock);  \
+})
+
+#define NVRAMWRITELOCK()                  \
+({                                        \
+	if (SAFE_TO_LOCK())                   \
+	        IORWLockWrite(_variableLock); \
+})
+
+#define NVRAMUNLOCK()                      \
+({                                         \
+	if (SAFE_TO_LOCK())                    \
+	        IORWLockUnlock(_variableLock); \
+})
+
+#define NVRAMLOCKASSERTHELD()                                   \
+({                                                              \
+	if (SAFE_TO_LOCK())                                         \
+	        IORWLockAssert(_variableLock, kIORWLockAssertHeld); \
+})
+
+#define NVRAMLOCKASSERTEXCLUSIVE()                               \
+({                                                               \
+	if (SAFE_TO_LOCK())                                          \
+	        IORWLockAssert(_variableLock, kIORWLockAssertWrite); \
+})
+
+enum NVRAMVersion {
+	kNVRAMVersionUnknown,
+	kNVRAMVersion1,       // Legacy, banks, 0x800 common partition size
+	kNVRAMVersion2,       // V1 but with (0x2000 - sizeof(struct apple_nvram_header) - sizeof(struct chrp_nvram_header)) common region
+	kNVRAMVersionMax
+};
+
+typedef struct {
+	NVRAMPartitionType        type;
+	UInt32                    offset;
+	UInt32                    size;
+	OSSharedPtr<OSDictionary> &dict;
+} NVRAMRegionInfo;
+
+// Guid for Apple System Boot variables
+// 40A0DDD2-77F8-4392-B4A3-1E7304206516
+UUID_DEFINE(gAppleSystemVariableGuid, 0x40, 0xA0, 0xDD, 0xD2, 0x77, 0xF8, 0x43, 0x92, 0xB4, 0xA3, 0x1E, 0x73, 0x04, 0x20, 0x65, 0x16);
+
+// Apple NVRAM Variable namespace (APPLE_VENDOR_OS_VARIABLE_GUID)
+// 7C436110-AB2A-4BBB-A880-FE41995C9F82
+UUID_DEFINE(gAppleNVRAMGuid, 0x7C, 0x43, 0x61, 0x10, 0xAB, 0x2A, 0x4B, 0xBB, 0xA8, 0x80, 0xFE, 0x41, 0x99, 0x5C, 0x9F, 0x82);
+
+static TUNABLE(bool, gNVRAMLogging, "nvram-log", false);
+static bool gInternalBuild = false;
+
+// allowlist variables from macboot that need to be set/get from system region if present
+static const char * const gNVRAMSystemList[] = {
+	"allow-root-hash-mismatch",
+	"auto-boot",
+	"auto-boot-halt-stage",
+	"base-system-path",
+	"boot-args",
+	"boot-command",
+	"boot-image",
+	"bootdelay",
+	"com.apple.System.boot-nonce",
+	"darkboot",
+	"emu",
+	"one-time-boot-command", // Needed for diags customer install flows
+	"policy-nonce-digests",
+	"prevent-restores", // Keep for factory <rdar://problem/70476321>
+	"prev-lang:kbd",
+	"root-live-fs",
+	"sep-debug-args", // Needed to simplify debug flows for SEP
+	"StartupMute", // Set by customers via nvram tool
+	"SystemAudioVolume",
+	"SystemAudioVolumeExtension",
+	"SystemAudioVolumeSaved",
+	nullptr
+};
+
+typedef struct {
+	const char *name;
+	IONVRAMVariableType type;
+} VariableTypeEntry;
+
+static const
+VariableTypeEntry gVariableTypes[] = {
+	{"auto-boot?", kOFVariableTypeBoolean},
+	{"boot-args", kOFVariableTypeString},
+	{"boot-command", kOFVariableTypeString},
+	{"boot-device", kOFVariableTypeString},
+	{"boot-file", kOFVariableTypeString},
+	{"boot-screen", kOFVariableTypeString},
+	{"boot-script", kOFVariableTypeString},
+	{"console-screen", kOFVariableTypeString},
+	{"default-client-ip", kOFVariableTypeString},
+	{"default-gateway-ip", kOFVariableTypeString},
+	{"default-mac-address?", kOFVariableTypeBoolean},
+	{"default-router-ip", kOFVariableTypeString},
+	{"default-server-ip", kOFVariableTypeString},
+	{"default-subnet-mask", kOFVariableTypeString},
+	{"diag-device", kOFVariableTypeString},
+	{"diag-file", kOFVariableTypeString},
+	{"diag-switch?", kOFVariableTypeBoolean},
+	{"fcode-debug?", kOFVariableTypeBoolean},
+	{"input-device", kOFVariableTypeString},
+	{"input-device-1", kOFVariableTypeString},
+	{"little-endian?", kOFVariableTypeBoolean},
+	{"load-base", kOFVariableTypeNumber},
+	{"mouse-device", kOFVariableTypeString},
+	{"nvramrc", kOFVariableTypeString},
+	{"oem-banner", kOFVariableTypeString},
+	{"oem-banner?", kOFVariableTypeBoolean},
+	{"oem-logo", kOFVariableTypeString},
+	{"oem-logo?", kOFVariableTypeBoolean},
+	{"output-device", kOFVariableTypeString},
+	{"output-device-1", kOFVariableTypeString},
+	{"pci-probe-list", kOFVariableTypeNumber},
+	{"pci-probe-mask", kOFVariableTypeNumber},
+	{"real-base", kOFVariableTypeNumber},
+	{"real-mode?", kOFVariableTypeBoolean},
+	{"real-size", kOFVariableTypeNumber},
+	{"screen-#columns", kOFVariableTypeNumber},
+	{"screen-#rows", kOFVariableTypeNumber},
+	{"security-mode", kOFVariableTypeString},
+	{"selftest-#megs", kOFVariableTypeNumber},
+	{"use-generic?", kOFVariableTypeBoolean},
+	{"use-nvramrc?", kOFVariableTypeBoolean},
+	{"virt-base", kOFVariableTypeNumber},
+	{"virt-size", kOFVariableTypeNumber},
+
+#if !defined(__x86_64__)
+	{"acc-cm-override-charger-count", kOFVariableTypeNumber},
+	{"acc-cm-override-count", kOFVariableTypeNumber},
+	{"acc-mb-ld-lifetime", kOFVariableTypeNumber},
+	{"com.apple.System.boot-nonce", kOFVariableTypeString},
+	{"darkboot", kOFVariableTypeBoolean},
+	{"enter-tdm-mode", kOFVariableTypeBoolean},
+#endif /* !defined(__x86_64__) */
+	{nullptr, kOFVariableTypeData} // Default type to return
+};
+
+union VariablePermission {
+	struct {
+		uint64_t UserWrite            :1;
+		uint64_t RootRequired         :1;
+		uint64_t KernelOnly           :1;
+		uint64_t ResetNVRAMOnlyDelete :1;
+		uint64_t NeverAllowedToDelete :1;
+		uint64_t SystemReadHidden     :1;
+		uint64_t FullAccess           :1;
+		uint64_t Reserved:57;
+	} Bits;
+	uint64_t Uint64;
+};
+
+typedef struct {
+	const char *name;
+	VariablePermission p;
+} VariablePermissionEntry;
+
+static const
+VariablePermissionEntry gVariablePermissions[] = {
+	{"aapl,pci", .p.Bits.RootRequired = 1},
+	{"battery-health", .p.Bits.RootRequired = 1,
+	 .p.Bits.NeverAllowedToDelete = 1},
+	{"boot-image", .p.Bits.UserWrite = 1},
+	{"com.apple.System.fp-state", .p.Bits.KernelOnly = 1},
+	{"fm-account-masked", .p.Bits.RootRequired = 1,
+	 .p.Bits.NeverAllowedToDelete = 1},
+	{"fm-activation-locked", .p.Bits.RootRequired = 1,
+	 .p.Bits.NeverAllowedToDelete = 1},
+	{"fm-spkeys", .p.Bits.RootRequired = 1,
+	 .p.Bits.NeverAllowedToDelete = 1},
+	{"fm-spstatus", .p.Bits.RootRequired = 1,
+	 .p.Bits.NeverAllowedToDelete = 1},
+	{"policy-nonce-digests", .p.Bits.ResetNVRAMOnlyDelete = 1}, // Deleting this via user triggered obliterate leave J273a unable to boot
+	{"recoveryos-passcode-blob", .p.Bits.SystemReadHidden = 1},
+	{"security-password", .p.Bits.RootRequired = 1},
+	{"system-passcode-lock-blob", .p.Bits.SystemReadHidden = 1},
+
+#if !defined(__x86_64__)
+	{"acc-cm-override-charger-count", .p.Bits.KernelOnly = 1},
+	{"acc-cm-override-count", .p.Bits.KernelOnly = 1},
+	{"acc-mb-ld-lifetime", .p.Bits.KernelOnly = 1},
+	{"backlight-level", .p.Bits.UserWrite = 1},
+	{"backlight-nits", .p.Bits.UserWrite = 1},
+	{"com.apple.System.boot-nonce", .p.Bits.KernelOnly = 1},
+	{"com.apple.System.sep.art", .p.Bits.KernelOnly = 1},
+	{"darkboot", .p.Bits.UserWrite = 1},
+	{"nonce-seeds", .p.Bits.KernelOnly = 1},
+#endif /* !defined(__x86_64__) */
+
+	{nullptr, {.Bits.FullAccess = 1}} // Default access
+};
+
+static IONVRAMVariableType
+getVariableType(const char *propName)
+{
+	const VariableTypeEntry *entry;
+
+	entry = gVariableTypes;
+	while (entry->name != nullptr) {
+		if (strcmp(entry->name, propName) == 0) {
+			break;
+		}
+		entry++;
+	}
+
+	return entry->type;
+}
+
+static IONVRAMVariableType
+getVariableType(const OSSymbol *propSymbol)
+{
+	return getVariableType(propSymbol->getCStringNoCopy());
+}
+
+static VariablePermission
+getVariablePermission(const char *propName)
+{
+	const VariablePermissionEntry *entry;
+
+	entry = gVariablePermissions;
+	while (entry->name != nullptr) {
+		if (strcmp(entry->name, propName) == 0) {
+			break;
+		}
+		entry++;
+	}
+
+	return entry->p;
+}
+
+static bool
+variableInAllowList(const char *varName)
+{
+	unsigned int i = 0;
+
+	while (gNVRAMSystemList[i] != nullptr) {
+		if (strcmp(varName, gNVRAMSystemList[i]) == 0) {
+			return true;
+		}
+		i++;
+	}
+
+	return false;
+}
+
+static bool
+verifyWriteSizeLimit(const uuid_t *varGuid, const char *variableName, size_t propDataSize)
+{
+	if (variableInAllowList(variableName)) {
+		if (strnstr(variableName, "breadcrumbs", strlen(variableName)) != NULL) {
+			return propDataSize <= 1024;
+		} else {
+			return propDataSize <= 768;
+		}
+	}
+
+	return true;
+}
+
+#if defined(DEBUG) || defined(DEVELOPMENT)
+static const char *
+getNVRAMOpString(IONVRAMOperation op)
+{
+	switch (op) {
+	case kIONVRAMOperationRead:
+		return "Read";
+	case kIONVRAMOperationWrite:
+		return "Write";
+	case kIONVRAMOperationDelete:
+		return "Delete";
+	case kIONVRAMOperationObliterate:
+		return "Obliterate";
+	case kIONVRAMOperationReset:
+		return "Reset";
+	case kIONVRAMOperationInit:
+		return "Init";
+	default:
+		return "Unknown";
+	}
+}
+#endif
+
+static bool
+verifyPermission(IONVRAMOperation op, const uuid_t *varGuid, const char *varName)
+{
+	VariablePermission perm;
+	bool kernel, writeEntitled, readEntitled, allowList, systemGuid, systemEntitled, systemInternalEntitled, systemAllow, systemReadHiddenAllow;
+	bool admin = false;
+	bool ok = false;
+
+	perm = getVariablePermission(varName);
+
+	kernel = current_task() == kernel_task;
+
+	if (perm.Bits.KernelOnly) {
+		DEBUG_INFO("KernelOnly access for %s, kernel=%d\n", varName, kernel);
+		ok = kernel;
+		goto exit;
+	}
+
+	allowList              = variableInAllowList(varName);
+	systemGuid             = uuid_compare(*varGuid, gAppleSystemVariableGuid) == 0;
+	admin                  = IOUserClient::clientHasPrivilege(current_task(), kIONVRAMPrivilege) == kIOReturnSuccess;
+	writeEntitled          = IOCurrentTaskHasEntitlement(kIONVRAMWriteAccessKey);
+	readEntitled           = IOCurrentTaskHasEntitlement(kIONVRAMReadAccessKey);
+	systemEntitled         = IOCurrentTaskHasEntitlement(kIONVRAMSystemAllowKey);
+	systemInternalEntitled = IOCurrentTaskHasEntitlement(kIONVRAMSystemInternalAllowKey);
+	systemReadHiddenAllow  = IOCurrentTaskHasEntitlement(kIONVRAMSystemHiddenAllowKey);
+
+	systemAllow = systemEntitled || (systemInternalEntitled && gInternalBuild) || kernel;
+
+	switch (op) {
+	case kIONVRAMOperationRead:
+		if (systemGuid && perm.Bits.SystemReadHidden) {
+			ok = systemReadHiddenAllow;
+		} else if (kernel || admin || readEntitled || perm.Bits.FullAccess) {
+			ok = true;
+		}
+		break;
+
+	case kIONVRAMOperationWrite:
+		if (kernel || perm.Bits.UserWrite || admin || writeEntitled) {
+			if (systemGuid) {
+				if (allowList) {
+					if (!systemAllow) {
+						DEBUG_ERROR("Allowed write to system region when NOT entitled for %s\n", varName);
+					}
+				} else if (!systemAllow) {
+					DEBUG_ERROR("Not entitled for system region writes for %s\n", varName);
+					break;
+				}
+			}
+			ok = true;
+		}
+		break;
+
+	case kIONVRAMOperationDelete:
+	case kIONVRAMOperationObliterate:
+	case kIONVRAMOperationReset:
+		if (perm.Bits.NeverAllowedToDelete) {
+			DEBUG_INFO("Never allowed to delete %s\n", varName);
+			break;
+		} else if ((op == kIONVRAMOperationObliterate) && perm.Bits.ResetNVRAMOnlyDelete) {
+			DEBUG_INFO("Not allowed to obliterate %s\n", varName);
+			break;
+		} else if ((op == kIONVRAMOperationDelete) && perm.Bits.ResetNVRAMOnlyDelete) {
+			DEBUG_INFO("Only allowed to delete %s via NVRAM reset\n", varName);
+			break;
+		}
+
+		if (kernel || perm.Bits.UserWrite || admin || writeEntitled) {
+			if (systemGuid) {
+				if (allowList) {
+					if (!systemAllow) {
+						DEBUG_ERROR("Allowed delete to system region when NOT entitled for %s\n", varName);
+					}
+				} else if (!systemAllow) {
+					DEBUG_ERROR("Not entitled for system region deletes for %s\n", varName);
+					break;
+				}
+			}
+			ok = true;
+		}
+		break;
+
+	case kIONVRAMOperationInit:
+		break;
+	}
+
+exit:
+	DEBUG_INFO("Permission for %s of %s %s: kernel=%d, admin=%d, writeEntitled=%d, readEntitled=%d, systemGuid=%d, systemEntitled=%d, systemInternalEntitled=%d, systemReadHiddenAllow=%d, UserWrite=%d\n",
+	    getNVRAMOpString(op), varName, ok ? "granted" : "denied", kernel, admin, writeEntitled, readEntitled, systemGuid, systemEntitled, systemInternalEntitled, systemReadHiddenAllow, perm.Bits.UserWrite);
+	return ok;
+}
+
+static bool
+verifyPermission(IONVRAMOperation op, const uuid_t *varGuid, const OSSymbol *varName)
+{
+	return verifyPermission(op, varGuid, varName->getCStringNoCopy());
+}
+
+/*
+ * Parse a variable name of the form "GUID:name".
+ * If the name cannot be parsed, substitute the Apple global variable GUID.
+ * Returns TRUE if a GUID was found in the name, FALSE otherwise.
+ * The guidResult and nameResult arguments may be nullptr if you just want
+ * to check the format of the string.
+ */
+static bool
+parseVariableName(const char *key, uuid_t *guidResult, const char **nameResult)
+{
+	uuid_string_t temp    = {0};
+	size_t        keyLen  = strlen(key);
+	bool          ok      = false;
+	const char    *name   = key;
+	uuid_t        guid;
+
+	if (keyLen > sizeof(temp)) {
+		// check for at least UUID + ":" + more
+		memcpy(temp, key, sizeof(temp) - 1);
+
+		if ((uuid_parse(temp, guid) == 0) &&
+		    (key[sizeof(temp) - 1] == ':')) {
+			name = key + sizeof(temp);
+			ok     = true;
+		}
+	}
+
+	if (guidResult) {
+		ok ? uuid_copy(*guidResult, guid) : uuid_copy(*guidResult, gAppleNVRAMGuid);
+	}
+	if (nameResult) {
+		*nameResult = name;
+	}
+
+	return false;
+}
+
+static bool
+skipKey(const OSSymbol *aKey)
+{
+	return aKey->isEqualTo(kIOClassNameOverrideKey) ||
+	       aKey->isEqualTo(kIOBSDNameKey) ||
+	       aKey->isEqualTo(kIOBSDNamesKey) ||
+	       aKey->isEqualTo(kIOBSDMajorKey) ||
+	       aKey->isEqualTo(kIOBSDMinorKey) ||
+	       aKey->isEqualTo(kIOBSDUnitKey) ||
+	       aKey->isEqualTo(kIOUserServicePropertiesKey) ||
+	       aKey->isEqualTo(kIOMatchCategoryKey);
+}
+
+// ************************** IODTNVRAMDiags ****************************
+
+#define kIODTNVRAMDiagsStatsKey   "Stats"
+#define kIODTNVRAMDiagsInitKey    "Init"
+#define kIODTNVRAMDiagsReadKey    "Read"
+#define kIODTNVRAMDiagsWriteKey   "Write"
+#define kIODTNVRAMDiagsDeleteKey  "Delete"
+#define kIODTNVRAMDiagsNameKey    "Name"
+#define kIODTNVRAMDiagsSizeKey    "Size"
+#define kIODTNVRAMDiagsPresentKey "Present"
+
+// private IOService based class for publishing diagnostic info for IODTNVRAM
+class IODTNVRAMDiags : public IOService
+{
+	OSDeclareDefaultStructors(IODTNVRAMDiags)
+private:
+	IODTNVRAM                 *_provider;
+	IORWLock                  *_variableLock;
+	OSSharedPtr<OSDictionary> _stats;
+
+	bool serializeStats(void *, OSSerialize * serializer);
+
+public:
+	bool start(IOService * provider, IORWLock *lock);
+	void logVariable(NVRAMPartitionType region, IONVRAMOperation op, const char *name, void *data);
+};
+
+OSDefineMetaClassAndStructors(IODTNVRAMDiags, IOService)
+
+bool
+IODTNVRAMDiags::start(IOService * provider, IORWLock *lock)
+{
+	OSSharedPtr<OSSerializer> serializer;
+
+	require(super::start(provider), error);
+
+	_variableLock = lock;
+	require(_variableLock, error);
+
+	_provider = OSDynamicCast(IODTNVRAM, provider);
+	require(_provider != nullptr, error);
+
+	_stats = OSDictionary::withCapacity(1);
+	require(_stats != nullptr, error);
+
+	serializer = OSSerializer::forTarget(this, OSMemberFunctionCast(OSSerializerCallback, this, &IODTNVRAMDiags::serializeStats));
+	require(serializer != nullptr, error);
+
+	setProperty(kIODTNVRAMDiagsStatsKey, serializer.get());
+
+	registerService();
+
+	return true;
+
+error:
+	stop(provider);
+
+	return false;
+}
+
+void
+IODTNVRAMDiags::logVariable(NVRAMPartitionType region, IONVRAMOperation op, const char *name, void *data)
+{
+	// "Stats"        : OSDictionary
+	// - "XX:varName" : OSDictionary, XX is the region value prefix to distinguish which dictionary the variable is in
+	//   - "Init"     : OSBoolean True/present if variable present at initialization
+	//   - "Read"     : OSNumber count
+	//   - "Write"    : OSNumber count
+	//   - "Delete"   : OSNumber count
+	//   - "Size"     : OSNumber size, latest size from either init or write
+	//   - "Present"  : OSBoolean True/False if variable is present or not
+	char * entryKey;
+	size_t entryKeySize;
+	OSSharedPtr<OSDictionary> existingEntry;
+	OSSharedPtr<OSNumber> currentCount;
+	OSSharedPtr<OSNumber> varSize;
+	const char * opCountKey = nullptr;
+
+	entryKeySize = strlen("XX:") + strlen(name) +  1;
+	entryKey = IONewData(char, entryKeySize);
+	require(entryKey, exit);
+
+	snprintf(entryKey, entryKeySize, "%02X:%s", region, name);
+
+	NVRAMWRITELOCK();
+	existingEntry.reset(OSDynamicCast(OSDictionary, _stats->getObject(entryKey)), OSRetain);
+
+	if (existingEntry == nullptr) {
+		existingEntry = OSDictionary::withCapacity(4);
+	}
+
+	switch (op) {
+	case kIONVRAMOperationRead:
+		opCountKey = kIODTNVRAMDiagsReadKey;
+		if (existingEntry->getObject(kIODTNVRAMDiagsPresentKey) == nullptr) {
+			existingEntry->setObject(kIODTNVRAMDiagsPresentKey, kOSBooleanFalse);
+		}
+		break;
+	case kIONVRAMOperationWrite:
+		opCountKey = kIODTNVRAMDiagsWriteKey;
+		varSize = OSNumber::withNumber((size_t)data, 64);
+		existingEntry->setObject(kIODTNVRAMDiagsSizeKey, varSize);
+		existingEntry->setObject(kIODTNVRAMDiagsPresentKey, kOSBooleanTrue);
+		break;
+	case kIONVRAMOperationDelete:
+	case kIONVRAMOperationObliterate:
+	case kIONVRAMOperationReset:
+		opCountKey = kIODTNVRAMDiagsDeleteKey;
+		existingEntry->setObject(kIODTNVRAMDiagsPresentKey, kOSBooleanFalse);
+		break;
+	case kIONVRAMOperationInit:
+		varSize = OSNumber::withNumber((size_t)data, 64);
+		existingEntry->setObject(kIODTNVRAMDiagsInitKey, varSize);
+		existingEntry->setObject(kIODTNVRAMDiagsSizeKey, varSize);
+		existingEntry->setObject(kIODTNVRAMDiagsPresentKey, kOSBooleanTrue);
+		break;
+	default:
+		goto exit;
+	}
+
+	if (opCountKey) {
+		currentCount.reset(OSDynamicCast(OSNumber, existingEntry->getObject(opCountKey)), OSRetain);
+
+		if (currentCount == nullptr) {
+			currentCount = OSNumber::withNumber(1, 64);
+		} else {
+			currentCount->addValue(1);
+		}
+
+		existingEntry->setObject(opCountKey, currentCount);
+	}
+
+	_stats->setObject(entryKey, existingEntry);
+	NVRAMUNLOCK();
+
+exit:
+	IODeleteData(entryKey, char, entryKeySize);
+
+	return;
+}
+
+bool
+IODTNVRAMDiags::serializeStats(void *, OSSerialize * serializer)
+{
+	bool ok;
+
+	NVRAMREADLOCK();
+	ok = _stats->serialize(serializer);
+	NVRAMUNLOCK();
+
+	return ok;
+}
+
+// ************************** IODTNVRAMVariables ****************************
+
+// private IOService based class for publishing distinct dictionary properties on
+// for easy ioreg access since the serializeProperties call is overloaded and is used
+// as variable access
+class IODTNVRAMVariables : public IOService
+{
+	OSDeclareDefaultStructors(IODTNVRAMVariables)
+private:
+	IODTNVRAM        *_provider;
+	OSDictionary     *_variables;
+	uuid_t           _guid;
+
+public:
+	bool                    init(const uuid_t *guid);
+	virtual bool            start(IOService * provider) APPLE_KEXT_OVERRIDE;
+	virtual IOReturn        setVariables(OSObject * properties);
+
+	virtual bool            serializeProperties(OSSerialize *s) const APPLE_KEXT_OVERRIDE;
+	virtual OSPtr<OSObject> copyProperty(const OSSymbol *aKey) const APPLE_KEXT_OVERRIDE;
+	virtual OSObject        *getProperty(const OSSymbol *aKey) const APPLE_KEXT_OVERRIDE;
+	virtual bool            setProperty(const OSSymbol *aKey, OSObject *anObject) APPLE_KEXT_OVERRIDE;
+	virtual IOReturn        setProperties(OSObject *properties) APPLE_KEXT_OVERRIDE;
+	virtual void            removeProperty(const OSSymbol *aKey) APPLE_KEXT_OVERRIDE;
+};
+
+OSDefineMetaClassAndStructors(IODTNVRAMVariables, IOService)
+
+bool
+IODTNVRAMVariables::init(const uuid_t *guid)
+{
+	require(super::init() && (guid != nullptr), fail);
+
+	uuid_copy(_guid, *guid);
+
+	return true;
+
+fail:
+	return false;
+}
+
+bool
+IODTNVRAMVariables::start(IOService * provider)
+{
+	if (!super::start(provider)) {
+		goto error;
+	}
+
+	_provider = OSDynamicCast(IODTNVRAM, provider);
+	if (_provider == nullptr) {
+		goto error;
+	}
+
+	registerService();
+
+	return true;
+
+error:
+	stop(provider);
+
+	return false;
+}
+
+IOReturn
+IODTNVRAMVariables::setVariables(OSObject * variables)
+{
+	if (OSDynamicCast(OSDictionary, variables)) {
+		OSSafeReleaseNULL(_variables);
+		_variables = OSDynamicCast(OSDictionary, variables);
+		variables->retain();
+	}
+
+	return kIOReturnSuccess;
+}
+
+bool
+IODTNVRAMVariables::serializeProperties(OSSerialize *s) const
+{
+	const OSSymbol                    *key;
+	OSSharedPtr<OSDictionary>         dict;
+	OSSharedPtr<OSCollectionIterator> iter;
+	OSSharedPtr<OSDictionary>         localVariables(_variables, OSRetain);
+	bool                              ok = false;
+
+	if (localVariables == nullptr) {
+		goto exit;
+	}
+
+	dict = OSDictionary::withCapacity(localVariables->getCount());
+	if (dict == nullptr) {
+		DEBUG_ERROR("No dictionary\n");
+		goto exit;
+	}
+
+	iter = OSCollectionIterator::withCollection(localVariables.get());
+	if (iter == nullptr) {
+		DEBUG_ERROR("failed to create iterator\n");
+		goto exit;
+	}
+
+	while ((key = OSDynamicCast(OSSymbol, iter->getNextObject()))) {
+		if (verifyPermission(kIONVRAMOperationRead, &_guid, key)) {
+			dict->setObject(key, localVariables->getObject(key));
+		}
+	}
+
+	ok = dict->serialize(s);
+
+exit:
+	DEBUG_INFO("ok=%d\n", ok);
+	return ok;
+}
+
+OSPtr<OSObject>
+IODTNVRAMVariables::copyProperty(const OSSymbol *aKey) const
+{
+	if (_provider && !skipKey(aKey)) {
+		DEBUG_INFO("aKey=%s\n", aKey->getCStringNoCopy());
+
+		return _provider->copyPropertyWithGUIDAndName(&_guid, aKey->getCStringNoCopy());
+	} else {
+		return nullptr;
+	}
+}
+
+OSObject *
+IODTNVRAMVariables::getProperty(const OSSymbol *aKey) const
+{
+	OSSharedPtr<OSObject> theObject = copyProperty(aKey);
+
+	return theObject.get();
+}
+
+bool
+IODTNVRAMVariables::setProperty(const OSSymbol *aKey, OSObject *anObject)
+{
+	if (_provider) {
+		return _provider->setPropertyWithGUIDAndName(&_guid, aKey->getCStringNoCopy(), anObject) == kIOReturnSuccess;
+	} else {
+		return false;
+	}
+}
+
+IOReturn
+IODTNVRAMVariables::setProperties(OSObject *properties)
+{
+	IOReturn                          ret = kIOReturnSuccess;
+	OSObject                          *object;
+	const OSSymbol                    *key;
+	OSDictionary                      *dict;
+	OSSharedPtr<OSCollectionIterator> iter;
+
+	if (_provider) {
+		dict = OSDynamicCast(OSDictionary, properties);
+		if (dict == nullptr) {
+			DEBUG_ERROR("Not a dictionary\n");
+			return kIOReturnBadArgument;
+		}
+
+		iter = OSCollectionIterator::withCollection(dict);
+		if (iter == nullptr) {
+			DEBUG_ERROR("Couldn't create iterator\n");
+			return kIOReturnBadArgument;
+		}
+
+		while (ret == kIOReturnSuccess) {
+			key = OSDynamicCast(OSSymbol, iter->getNextObject());
+			if (key == nullptr) {
+				break;
+			}
+
+			object = dict->getObject(key);
+			if (object == nullptr) {
+				continue;
+			}
+
+			ret = setProperty(key, object);
+		}
+	} else {
+		ret = kIOReturnNotReady;
+	}
+
+	DEBUG_INFO("ret=%#08x\n", ret);
+
+	return ret;
+}
+
+void
+IODTNVRAMVariables::removeProperty(const OSSymbol *aKey)
+{
+	if (_provider) {
+		_provider->removePropertyWithGUIDAndName(&_guid, aKey->getCStringNoCopy());
+	}
+}
+
+
+// **************************** IODTNVRAM *********************************
+
+bool
+IODTNVRAM::init(IORegistryEntry *old, const IORegistryPlane *plane)
+{
+	OSSharedPtr<OSDictionary> dict;
+
+	require(super::init(old, plane), fail);
+
+#if XNU_TARGET_OS_OSX
+#if CONFIG_CSR
+	gInternalBuild = (csr_check(CSR_ALLOW_APPLE_INTERNAL) == 0);
+	DEBUG_INFO("gInternalBuild = %d\n", gInternalBuild);
+#endif // CONFIG_CSR
+#endif // XNU_TARGET_OS_OSX
+
+	_variableLock = IORWLockAlloc();
+	require(_variableLock != nullptr, fail);
+
+	_controllerLock = IOLockAlloc();
+	require(_controllerLock != nullptr, fail);
+
+	dict =  OSDictionary::withCapacity(1);
+	require(dict != nullptr, fail);
+
+	setPropertyTable(dict.get());
+	dict.reset();
+
+	_nvramSize = getNVRAMSize();
+	if (_nvramSize == 0) {
+		DEBUG_ERROR("NVRAM : Error - default size not specified in DT\n");
+		return false;
+	}
+	// partition offsets are UInt16 (bytes / 0x10) + 1
+	if (_nvramSize > 0xFFFF * 0x10) {
+		DEBUG_ERROR("NVRAM : truncating _nvramSize from %ld\n", (long) _nvramSize);
+		_nvramSize = 0xFFFF * 0x10;
+	}
+	_nvramImage = IONewData(UInt8, _nvramSize);
+	require(_nvramImage != nullptr, fail);
+
+	_nvramPartitionOffsets = OSDictionary::withCapacity(1);
+	require(_nvramPartitionOffsets != nullptr, fail);
+
+	_nvramPartitionLengths = OSDictionary::withCapacity(1);
+	require(_nvramPartitionLengths != nullptr, fail);
+
+	_registryPropertiesKey = OSSymbol::withCStringNoCopy("aapl,pci");
+	require(_registryPropertiesKey != nullptr, fail);
+
+	return true;
+
+fail:
+	return false;
+}
+
+bool
+IODTNVRAM::start(IOService *provider)
+{
+	IOReturn ret;
+	OSSharedPtr<OSNumber> version;
+
+	require(super::start(provider), fail);
+
+	// Check if _nvramImage is created from our init() function.
+	// If not, skip any additional initialization being done here.
+	// This is not an error we just need to successfully exit this function to allow
+	// AppleEFIRuntime to proceed and take over operation
+	require_action(_nvramImage, no_common, DEBUG_INFO("x86 init\n"));
+
+	_diags = new IODTNVRAMDiags;
+	if (!_diags || !_diags->init()) {
+		DEBUG_ERROR("Unable to create/init the diags service\n");
+		OSSafeReleaseNULL(_diags);
+		goto fail;
+	}
+
+	if (!_diags->attach(this)) {
+		DEBUG_ERROR("Unable to attach the diags service!\n");
+		OSSafeReleaseNULL(_diags);
+		goto fail;
+	}
+
+	if (!_diags->start(this, _variableLock)) {
+		DEBUG_ERROR("Unable to start the diags service!\n");
+		_diags->detach(this);
+		OSSafeReleaseNULL(_diags);
+		goto fail;
+	}
+
+	// <rdar://problem/9529235> race condition possible between
+	// IODTNVRAM and IONVRAMController (restore loses boot-args)
+	initProxyData();
+
+	version = OSNumber::withNumber(_nvramVersion, 32);
+	_diags->setProperty(kCurrentNVRAMVersionKey, version.get());
+
+	// Require at least the common partition to be present and error free
+	require(_commonDict != nullptr, fail);
+
+	if (_systemPartitionSize) {
+		_systemService = new IODTNVRAMVariables;
+
+		if (!_systemService || !_systemService->init(&gAppleSystemVariableGuid)) {
+			DEBUG_ERROR("Unable to start the system service!\n");
+			OSSafeReleaseNULL(_systemService);
+			goto no_system;
+		}
+
+		_systemService->setName("options-system");
+
+		if (!_systemService->attach(this)) {
+			DEBUG_ERROR("Unable to attach the system service!\n");
+			OSSafeReleaseNULL(_systemService);
+			goto no_system;
+		}
+
+		if (!_systemService->start(this)) {
+			DEBUG_ERROR("Unable to start the system service!\n");
+			_systemService->detach(this);
+			OSSafeReleaseNULL(_systemService);
+			goto no_system;
+		}
+	}
+
+no_system:
+	if (_commonPartitionSize) {
+		_commonService = new IODTNVRAMVariables;
+
+		if (!_commonService || !_commonService->init(&gAppleNVRAMGuid)) {
+			DEBUG_ERROR("Unable to start the common service!\n");
+			OSSafeReleaseNULL(_commonService);
+			goto no_common;
+		}
+
+		_commonService->setName("options-common");
+
+		if (!_commonService->attach(this)) {
+			DEBUG_ERROR("Unable to attach the common service!\n");
+			OSSafeReleaseNULL(_commonService);
+			goto no_common;
+		}
+
+		if (!_commonService->start(this)) {
+			DEBUG_ERROR("Unable to start the common service!\n");
+			_commonService->detach(this);
+			OSSafeReleaseNULL(_commonService);
+			goto no_common;
+		}
+	}
+
+	ret = serializeVariables();
+	DEBUG_INFO("serializeVariables ret=%#08x\n", ret);
+
+no_common:
+	return true;
+
+fail:
+	stop(provider);
+	return false;
+}
+
+void
+IODTNVRAM::initProxyData(void)
+{
+	OSSharedPtr<IORegistryEntry> entry;
+	const char                   *key = "nvram-proxy-data";
+	OSData                       *data;
+	const void                   *bytes;
+
+	entry = IORegistryEntry::fromPath("/chosen", gIODTPlane);
+	if (entry != nullptr) {
+		OSSharedPtr<OSObject> prop = entry->copyProperty(key);
+		if (prop != nullptr) {
+			data = OSDynamicCast(OSData, prop.get());
+			if (data != nullptr) {
+				bytes = data->getBytesNoCopy();
+				if ((bytes != nullptr) && (data->getLength() <= _nvramSize)) {
+					bcopy(bytes, _nvramImage, data->getLength());
+					initNVRAMImage();
+					_isProxied = true;
+				}
+			}
+		}
+#if defined(RELEASE)
+		entry->removeProperty(key);
+#endif
+	}
+}
+
+UInt32
+IODTNVRAM::getNVRAMSize(void)
+{
+	OSSharedPtr<IORegistryEntry> entry;
+	const char                   *key = "nvram-bank-size";
+	OSData                       *data;
+	UInt32                       size = 0;
+
+	entry = IORegistryEntry::fromPath("/chosen", gIODTPlane);
+	if (entry != nullptr) {
+		OSSharedPtr<OSObject> prop = entry->copyProperty(key);
+		if (prop != nullptr) {
+			data = OSDynamicCast(OSData, prop.get());
+			if (data != nullptr) {
+				size = *((UInt32*)data->getBytesNoCopy());
+				DEBUG_ALWAYS("NVRAM size is %u bytes\n", (unsigned int) size);
+			}
+		}
+	}
+	return size;
+}
+
+void
+IODTNVRAM::registerNVRAMController(IONVRAMController *nvram)
+{
+	IOReturn ret;
+	OSSharedPtr<OSNumber> version;
+
+	if (_nvramController != nullptr) {
+		DEBUG_ERROR("Duplicate controller set\n");
+		return;
+	}
+
+	DEBUG_INFO("setting controller\n");
+
+	CONTROLLERLOCK();
+	_nvramController = nvram;
+	CONTROLLERUNLOCK();
+
+	// <rdar://problem/9529235> race condition possible between
+	// IODTNVRAM and IONVRAMController (restore loses boot-args)
+	if (!_isProxied) {
+		DEBUG_INFO("Reading non-proxied NVRAM data\n");
+		_nvramController->read(0, _nvramImage, _nvramSize);
+		initNVRAMImage();
+	}
+
+	ret = serializeVariables();
+	DEBUG_INFO("serializeVariables ret=%#08x\n", ret);
+
+	return;
+}
+
+static const char *
+get_bank_version_string(int version)
+{
+	switch (version) {
+	case kNVRAMVersion1:
+		return NVRAM_CHRP_APPLE_HEADER_NAME_V1;
+	case kNVRAMVersion2:
+		return NVRAM_CHRP_APPLE_HEADER_NAME_V2;
+	default:
+		return "Unknown";
+	}
+}
+
+static UInt32
+adler32(const UInt8 *buffer, size_t length)
+{
+	UInt32 offset;
+	UInt32 adler, lowHalf, highHalf;
+
+	lowHalf = 1;
+	highHalf = 0;
+
+	for (offset = 0; offset < length; offset++) {
+		if ((offset % 5000) == 0) {
+			lowHalf  %= 65521L;
+			highHalf %= 65521L;
+		}
+
+		lowHalf += buffer[offset];
+		highHalf += lowHalf;
+	}
+
+	lowHalf  %= 65521L;
+	highHalf %= 65521L;
+
+	adler = (highHalf << 16) | lowHalf;
+
+	return adler;
+}
+
+static UInt32
+nvram_get_adler(UInt8 *buf, int version)
+{
+	return ((struct apple_nvram_header *)buf)->adler;
+}
+
+static UInt32
+adler32_with_version(const UInt8 *buf, size_t len, int version)
+{
+	size_t offset;
+
+	switch (version) {
+	case kNVRAMVersion1:
+	case kNVRAMVersion2:
+		offset = offsetof(struct apple_nvram_header, generation);
+		break;
+	default:
+		return 0;
+	}
+
+	return adler32(buf + offset, len - offset);
+}
+
+static UInt8
+chrp_checksum(const struct chrp_nvram_header *hdr)
+{
+	UInt16 sum;
+	const UInt8 *p;
+	const UInt8 *begin = (const uint8_t *)hdr + offsetof(struct chrp_nvram_header, len);
+	const UInt8 *end = (const uint8_t *)hdr + offsetof(struct chrp_nvram_header, data);
+
+	// checksum the header (minus the checksum itself)
+	sum = hdr->sig;
+	for (p = begin; p < end; p++) {
+		sum += *p;
+	}
+	while (sum > 0xff) {
+		sum = (sum & 0xff) + (sum >> 8);
+	}
+
+	return sum & 0xff;
+}
+
+static IOReturn
+nvram_validate_header_v1v2(const UInt8 * buf, UInt32 *generation, int version)
+{
+	IOReturn result = kIOReturnError;
+	UInt8 checksum;
+	const char *header_string = get_bank_version_string(version);
+	struct chrp_nvram_header *chrp_header = (struct chrp_nvram_header *)buf;
+	UInt32 local_gen = 0;
+
+	// <rdar://problem/73454488> Recovery Mode [Internal Build] 18D52-->18E141 [J307/308 Only]
+	// we can only compare the first "nvram" parts of the name as some devices have additional junk from
+	// a previous build likely copying past bounds of the "nvram" name in the const section
+	if (memcmp(header_string, chrp_header->name, strlen(header_string)) == 0) {
+		checksum = chrp_checksum(chrp_header);
+		if (checksum == chrp_header->cksum) {
+			result = kIOReturnSuccess;
+			local_gen = ((struct apple_nvram_header*)buf)->generation;
+
+			DEBUG_INFO("Found %s gen=%u\n", header_string, (unsigned int)local_gen);
+
+			if (generation) {
+				*generation = local_gen;
+			}
+		} else {
+			DEBUG_INFO("invalid checksum in header, found %#02x, expected %#02x\n", chrp_header->cksum, checksum);
+		}
+	} else {
+		DEBUG_INFO("invalid bank for \"%s\", name = %#02x %#02x %#02x %#02x\n", header_string,
+		    chrp_header->name[0],
+		    chrp_header->name[1],
+		    chrp_header->name[2],
+		    chrp_header->name[3]);
+	}
+
+	return result;
+}
+
+static int
+findNVRAMVersion(UInt8 *buf, size_t len, UInt32 *generation)
+{
+	NVRAMVersion version = kNVRAMVersionUnknown;
+
+	if (nvram_validate_header_v1v2(buf, generation, kNVRAMVersion1) == kIOReturnSuccess) {
+		version = kNVRAMVersion1;
+		goto exit;
+	}
+
+	if (nvram_validate_header_v1v2(buf, generation, kNVRAMVersion2) == kIOReturnSuccess) {
+		version = kNVRAMVersion2;
+		goto exit;
+	}
+
+	DEBUG_INFO("Unable to determine version, defaulting to V1\n");
+	version = kNVRAMVersion1;
+
+exit:
+	DEBUG_INFO("version=%u\n", version);
+	return version;
+}
+
+static void
+nvram_set_apple_header(UInt8 *buf, size_t len, UInt32 generation, int version)
+{
+	if (version == kNVRAMVersion1 ||
+	    version == kNVRAMVersion2) {
+		struct apple_nvram_header *apple_hdr = (struct apple_nvram_header *)buf;
+		generation += 1;
+		apple_hdr->generation = generation;
+		apple_hdr->adler = adler32_with_version(buf, len, version);
+	}
+}
+
+void
+IODTNVRAM::initNVRAMImage(void)
+{
+	char   partitionID[18];
+	UInt32 partitionOffset, partitionLength;
+	UInt32 currentLength, currentOffset = 0;
+	UInt32 hdr_adler, calculated_adler;
+
+	_commonPartitionOffset = 0xFFFFFFFF;
+	_systemPartitionOffset = 0xFFFFFFFF;
+
+	_nvramVersion = findNVRAMVersion(_nvramImage, _nvramSize, &_nvramGeneration);
+
+	hdr_adler = nvram_get_adler(_nvramImage, _nvramVersion);
+	calculated_adler = adler32_with_version(_nvramImage, _nvramSize, _nvramVersion);
+
+	if (hdr_adler != calculated_adler) {
+		panic("header adler %#08X != calculated_adler %#08X\n", (unsigned int)hdr_adler, (unsigned int)calculated_adler);
+		return;
+	}
+
+	// Look through the partitions to find the common and system partitions.
+	while (currentOffset < _nvramSize) {
+		bool common_partition;
+		bool system_partition;
+		chrp_nvram_header_t * header = (chrp_nvram_header_t *)(_nvramImage + currentOffset);
+		const uint8_t common_v1_name[sizeof(header->name)] = {NVRAM_CHRP_PARTITION_NAME_COMMON_V1};
+		const uint8_t common_v2_name[sizeof(header->name)] = {NVRAM_CHRP_PARTITION_NAME_COMMON_V2};
+		const uint8_t system_v1_name[sizeof(header->name)] = {NVRAM_CHRP_PARTITION_NAME_SYSTEM_V1};
+		const uint8_t system_v2_name[sizeof(header->name)] = {NVRAM_CHRP_PARTITION_NAME_SYSTEM_V2};
+
+		currentLength = header->len * NVRAM_CHRP_LENGTH_BLOCK_SIZE;
+
+		if (currentLength < sizeof(chrp_nvram_header_t)) {
+			break;
+		}
+
+		partitionOffset = currentOffset + sizeof(chrp_nvram_header_t);
+		partitionLength = currentLength - sizeof(chrp_nvram_header_t);
+
+		if ((partitionOffset + partitionLength) > _nvramSize) {
+			break;
+		}
+
+		common_partition = (memcmp(header->name, common_v1_name, sizeof(header->name)) == 0) ||
+		    (memcmp(header->name, common_v2_name, sizeof(header->name)) == 0);
+		system_partition = (memcmp(header->name, system_v1_name, sizeof(header->name)) == 0) ||
+		    (memcmp(header->name, system_v2_name, sizeof(header->name)) == 0);
+
+		if (common_partition) {
+			_commonPartitionOffset = partitionOffset;
+			_commonPartitionSize = partitionLength;
+		} else if (system_partition) {
+			_systemPartitionOffset = partitionOffset;
+			_systemPartitionSize = partitionLength;
+		} else {
+			OSSharedPtr<OSNumber> partitionOffsetNumber, partitionLengthNumber;
+
+			// Construct the partition ID from the signature and name.
+			snprintf(partitionID, sizeof(partitionID), "%#02x,", header->sig);
+			memcpy(partitionID + 5, header->name, sizeof(header->name));
+			partitionID[17] = '\0';
+
+			partitionOffsetNumber = OSNumber::withNumber(partitionOffset, 32);
+			partitionLengthNumber = OSNumber::withNumber(partitionLength, 32);
+
+			// Save the partition offset and length
+			_nvramPartitionOffsets->setObject(partitionID, partitionOffsetNumber.get());
+			_nvramPartitionLengths->setObject(partitionID, partitionLengthNumber.get());
+		}
+		currentOffset += currentLength;
+	}
+
+	DEBUG_ALWAYS("NVRAM : commonPartitionOffset - %#x, commonPartitionSize - %#x, systemPartitionOffset - %#x, systemPartitionSize - %#x\n",
+	    (unsigned int) _commonPartitionOffset, (unsigned int) _commonPartitionSize, (unsigned int) _systemPartitionOffset, (unsigned int) _systemPartitionSize);
+
+	_lastDeviceSync = 0;
+	_freshInterval = TRUE;          // we will allow sync() even before the first 15 minutes have passed.
+
+	initVariables();
+}
+
+void
+IODTNVRAM::syncInternal(bool rateLimit)
+{
+	IOReturn ret;
+
+	DEBUG_INFO("rateLimit=%d\n", rateLimit);
+
+	// Don't try to perform controller operations if none has been registered.
+	if (_nvramController == nullptr) {
+		return;
+	}
+
+	// Rate limit requests to sync. Drivers that need this rate limiting will
+	// shadow the data and only write to flash when they get a sync call
+	if (rateLimit) {
+		if (safeToSync() == false) {
+			DEBUG_INFO("safeToSync()=false\n");
+			return;
+		}
+	}
+
+	CONTROLLERLOCK();
+
+	_nvramGeneration++;
+	nvram_set_apple_header(_nvramImage, _nvramSize, _nvramGeneration, _nvramVersion);
+
+	ret = _nvramController->write(0, _nvramImage, _nvramSize);
+	DEBUG_INFO("nvramController->write() for gen=%u ret=%#08x\n", (unsigned int)_nvramGeneration, ret);
+
+	if (_diags && SAFE_TO_LOCK()) {
+		OSSharedPtr<OSNumber> generation = OSNumber::withNumber(_nvramGeneration, 32);
+		_diags->setProperty(kCurrentGenerationCountKey, generation.get());
+	}
+
+	DEBUG_INFO("Calling sync()\n");
+	_nvramController->sync();
+
+	CONTROLLERUNLOCK();
+}
+
+void
+IODTNVRAM::sync(void)
+{
+	syncInternal(false);
+}
+
+bool
+IODTNVRAM::serializeProperties(OSSerialize *s) const
+{
+	const OSSymbol                    *key;
+	OSSharedPtr<OSDictionary>         systemDict, commonDict, dict;
+	OSSharedPtr<OSCollectionIterator> iter;
+	bool                              ok = false;
+	unsigned int                      totalCapacity = 0;
+
+	NVRAMREADLOCK();
+	if (_commonDict) {
+		commonDict = OSDictionary::withDictionary(_commonDict.get());
+	}
+
+	if (_systemDict) {
+		systemDict = OSDictionary::withDictionary(_systemDict.get());
+	}
+	NVRAMUNLOCK();
+
+	totalCapacity += (commonDict != nullptr) ? commonDict->getCapacity() : 0;
+	totalCapacity += (systemDict != nullptr) ? systemDict->getCapacity() : 0;
+
+	dict = OSDictionary::withCapacity(totalCapacity);
+
+	if (dict == nullptr) {
+		DEBUG_ERROR("No dictionary\n");
+		goto exit;
+	}
+
+	// Copy system entries first if present then copy unique common entries
+	if (systemDict != nullptr) {
+		iter = OSCollectionIterator::withCollection(systemDict.get());
+		if (iter == nullptr) {
+			DEBUG_ERROR("failed to create iterator\n");
+			goto exit;
+		}
+
+		while ((key = OSDynamicCast(OSSymbol, iter->getNextObject()))) {
+			if (verifyPermission(kIONVRAMOperationRead, &gAppleSystemVariableGuid, key)) {
+				dict->setObject(key, systemDict->getObject(key));
+			}
+		}
+
+		iter.reset();
+	}
+
+	if (commonDict != nullptr) {
+		iter = OSCollectionIterator::withCollection(commonDict.get());
+		if (iter == nullptr) {
+			DEBUG_ERROR("failed to create common iterator\n");
+			goto exit;
+		}
+
+		while ((key = OSDynamicCast(OSSymbol, iter->getNextObject()))) {
+			if (dict->getObject(key) != nullptr) {
+				// Skip non uniques
+				continue;
+			}
+			if (verifyPermission(kIONVRAMOperationRead, &gAppleNVRAMGuid, key)) {
+				dict->setObject(key, commonDict->getObject(key));
+			}
+		}
+	}
+
+	ok = dict->serialize(s);
+
+exit:
+	DEBUG_INFO("ok=%d\n", ok);
+
+	return ok;
+}
+
+NVRAMPartitionType
+IODTNVRAM::getDictionaryType(const OSDictionary *dict) const
+{
+	if (dict == _commonDict) {
+		return kIONVRAMPartitionCommon;
+	} else if (dict == _systemDict) {
+		return kIONVRAMPartitionSystem;
+	} else {
+		return kIONVRAMPartitionTypeUnknown;
+	}
+}
+
+IOReturn
+IODTNVRAM::chooseDictionary(IONVRAMOperation operation, const uuid_t *varGuid, const char *variableName, OSDictionary **dict) const
+{
+	if (_systemDict != nullptr) {
+		bool systemGuid = uuid_compare(*varGuid, gAppleSystemVariableGuid) == 0;
+
+		if (variableInAllowList(variableName)) {
+			DEBUG_INFO("Using system dictionary due to allow list\n");
+			if (!systemGuid) {
+				DEBUG_ERROR("System GUID NOT used for %s\n", variableName);
+			}
+			*dict = _systemDict.get();
+		} else if (systemGuid) {
+			DEBUG_INFO("Using system dictionary via GUID\n");
+			*dict = _systemDict.get();
+		} else {
+			DEBUG_INFO("Using common dictionary\n");
+			*dict = _commonDict.get();
+		}
+		return kIOReturnSuccess;
+	} else if (_commonDict != nullptr) {
+		DEBUG_INFO("Defaulting to common dictionary\n");
+		*dict = _commonDict.get();
+		return kIOReturnSuccess;
+	}
+
+	return kIOReturnNotFound;
+}
+
+IOReturn
+IODTNVRAM::flushDict(const uuid_t *guid, IONVRAMOperation op)
+{
+	IOReturn err = kIOReturnSuccess;
+
+	if ((_systemDict != nullptr) && (uuid_compare(*guid, gAppleSystemVariableGuid) == 0)) {
+		const OSSymbol *key;
+		OSSharedPtr<OSDictionary> newDict;
+		OSSharedPtr<OSCollectionIterator> iter;
+
+		newDict = OSDictionary::withCapacity(_systemDict->getCapacity());
+		iter = OSCollectionIterator::withCollection(_systemDict.get());
+		if ((newDict == nullptr) || (iter == nullptr)) {
+			err = kIOReturnNoMemory;
+			goto exit;
+		}
+
+		while ((key = OSDynamicCast(OSSymbol, iter->getNextObject()))) {
+			if (!verifyPermission(op, &gAppleSystemVariableGuid, key)) {
+				newDict->setObject(key, _systemDict->getObject(key));
+			}
+		}
+
+		_systemDict = newDict;
+
+		DEBUG_INFO("system dictionary flushed\n");
+	} else if ((_commonDict != nullptr) && (uuid_compare(*guid, gAppleNVRAMGuid) == 0)) {
+		const OSSymbol *key;
+		OSSharedPtr<OSDictionary> newDict;
+		OSSharedPtr<OSCollectionIterator> iter;
+
+		newDict = OSDictionary::withCapacity(_commonDict->getCapacity());
+		iter = OSCollectionIterator::withCollection(_commonDict.get());
+		if ((newDict == nullptr) || (iter == nullptr)) {
+			err = kIOReturnNoMemory;
+			goto exit;
+		}
+
+		while ((key = OSDynamicCast(OSSymbol, iter->getNextObject()))) {
+			if (!verifyPermission(op, &gAppleNVRAMGuid, key)) {
+				newDict->setObject(key, _commonDict->getObject(key));
+			}
+		}
+
+		_commonDict = newDict;
+
+		DEBUG_INFO("common dictionary flushed\n");
+	}
+
+exit:
+	return err;
+}
+
+bool
+IODTNVRAM::handleSpecialVariables(const char *name, const uuid_t *guid, const OSObject *obj, IOReturn *error)
+{
+	IOReturn err = kIOReturnSuccess;
+	bool special = false;
+
+	NVRAMLOCKASSERTEXCLUSIVE();
+
+	// ResetNVRam flushes both regions in one call
+	// Obliterate can flush either separately
+	if (strcmp(name, "ObliterateNVRam") == 0) {
+		special = true;
+		err = flushDict(guid, kIONVRAMOperationObliterate);
+	} else if (strcmp(name, "ResetNVRam") == 0) {
+		special = true;
+		err = flushDict(&gAppleSystemVariableGuid, kIONVRAMOperationReset);
+
+		if (err != kIOReturnSuccess) {
+			goto exit;
+		}
+
+		err = flushDict(&gAppleNVRAMGuid, kIONVRAMOperationReset);
+	}
+
+exit:
+	if (error) {
+		*error = err;
+	}
+
+	return special;
+}
+
+OSSharedPtr<OSObject>
+IODTNVRAM::copyPropertyWithGUIDAndName(const uuid_t *guid, const char *name) const
+{
+	IOReturn              result;
+	OSDictionary          *dict;
+	OSSharedPtr<OSObject> theObject = nullptr;
+
+	result = chooseDictionary(kIONVRAMOperationRead, guid, name, &dict);
+	if (result != kIOReturnSuccess) {
+		DEBUG_INFO("No dictionary\n");
+		goto exit;
+	}
+
+	if (!verifyPermission(kIONVRAMOperationRead, guid, name)) {
+		DEBUG_INFO("Not privileged\n");
+		goto exit;
+	}
+
+	NVRAMREADLOCK();
+	theObject.reset(dict->getObject(name), OSRetain);
+	NVRAMUNLOCK();
+
+	if (_diags) {
+		_diags->logVariable(getDictionaryType(dict), kIONVRAMOperationRead, name, NULL);
+	}
+
+	if (theObject != nullptr) {
+		DEBUG_INFO("found data\n");
+	}
+
+exit:
+	return theObject;
+}
+
+OSSharedPtr<OSObject>
+IODTNVRAM::copyProperty(const OSSymbol *aKey) const
+{
+	const char            *variableName;
+	uuid_t                varGuid;
+
+	if (skipKey(aKey)) {
+		return nullptr;
+	}
+	DEBUG_INFO("aKey=%s\n", aKey->getCStringNoCopy());
+
+	parseVariableName(aKey->getCStringNoCopy(), &varGuid, &variableName);
+
+	return copyPropertyWithGUIDAndName(&varGuid, variableName);
+}
+
+OSSharedPtr<OSObject>
+IODTNVRAM::copyProperty(const char *aKey) const
+{
+	OSSharedPtr<const OSSymbol> keySymbol;
+	OSSharedPtr<OSObject>       theObject;
+
+	keySymbol = OSSymbol::withCString(aKey);
+	if (keySymbol != nullptr) {
+		theObject = copyProperty(keySymbol.get());
+	}
+
+	return theObject;
+}
+
+OSObject *
+IODTNVRAM::getProperty(const OSSymbol *aKey) const
+{
+	// The shared pointer gets released at the end of the function,
+	// and returns a view into theObject.
+	OSSharedPtr<OSObject> theObject = copyProperty(aKey);
+
+	return theObject.get();
+}
+
+OSObject *
+IODTNVRAM::getProperty(const char *aKey) const
+{
+	// The shared pointer gets released at the end of the function,
+	// and returns a view into theObject.
+	OSSharedPtr<OSObject> theObject = copyProperty(aKey);
+
+	return theObject.get();
+}
+
+IOReturn
+IODTNVRAM::setPropertyWithGUIDAndName(const uuid_t *guid, const char *name, OSObject *anObject)
+{
+	IOReturn              ret = kIOReturnSuccess;
+	bool                  remove = false;
+	OSString              *tmpString = nullptr;
+	OSSharedPtr<OSObject> propObject, oldObject;
+	OSSharedPtr<OSObject> sharedObject(anObject, OSRetain);
+	OSDictionary          *dict;
+	bool                  deletePropertyKey, syncNowPropertyKey, forceSyncNowPropertyKey;
+	bool                  ok;
+	size_t                propDataSize = 0;
+
+	deletePropertyKey = strncmp(name, kIONVRAMDeletePropertyKey, sizeof(kIONVRAMDeletePropertyKey)) == 0;
+	syncNowPropertyKey = strncmp(name, kIONVRAMSyncNowPropertyKey, sizeof(kIONVRAMSyncNowPropertyKey)) == 0;
+	forceSyncNowPropertyKey = strncmp(name, kIONVRAMForceSyncNowPropertyKey, sizeof(kIONVRAMForceSyncNowPropertyKey)) == 0;
+
+	if (deletePropertyKey) {
+		tmpString = OSDynamicCast(OSString, anObject);
+		if (tmpString != nullptr) {
+			const char *variableName;
+			uuid_t     varGuid;
+			IOReturn   removeRet;
+
+			parseVariableName(tmpString->getCStringNoCopy(), &varGuid, &variableName);
+			removeRet = removePropertyWithGUIDAndName(&varGuid, variableName);
+
+			DEBUG_INFO("kIONVRAMDeletePropertyKey found, removeRet=%#08x\n", removeRet);
+		} else {
+			DEBUG_INFO("kIONVRAMDeletePropertyKey value needs to be an OSString\n");
+			ret = kIOReturnError;
+		}
+		goto exit;
+	} else if (syncNowPropertyKey || forceSyncNowPropertyKey) {
+		tmpString = OSDynamicCast(OSString, anObject);
+		DEBUG_INFO("NVRAM sync key %s found\n", name);
+		if (tmpString != nullptr) {
+			// We still want to throttle NVRAM commit rate for SyncNow. ForceSyncNow is provided as a really big hammer.
+			syncInternal(syncNowPropertyKey);
+		} else {
+			DEBUG_INFO("%s value needs to be an OSString\n", name);
+			ret = kIOReturnError;
+		}
+		goto exit;
+	}
+
+	ret = chooseDictionary(kIONVRAMOperationWrite, guid, name, &dict);
+	if (ret != kIOReturnSuccess) {
+		DEBUG_INFO("No dictionary\n");
+		goto exit;
+	}
+
+	if (!verifyPermission(kIONVRAMOperationWrite, guid, name)) {
+		DEBUG_INFO("Not privileged\n");
+		ret = kIOReturnNotPrivileged;
+		goto exit;
+	}
+
+	// Make sure the object is of the correct type.
+	switch (getVariableType(name)) {
+	case kOFVariableTypeBoolean:
+		propObject = OSDynamicPtrCast<OSBoolean>(sharedObject);
+		break;
+
+	case kOFVariableTypeNumber:
+		propObject = OSDynamicPtrCast<OSNumber>(sharedObject);
+		break;
+
+	case kOFVariableTypeString:
+		propObject = OSDynamicPtrCast<OSString>(sharedObject);
+		if (propObject != nullptr) {
+			propDataSize = (OSDynamicPtrCast<OSString>(propObject))->getLength();
+
+			if ((strncmp(name, kIONVRAMBootArgsKey, sizeof(kIONVRAMBootArgsKey)) == 0) && (propDataSize >= BOOT_LINE_LENGTH)) {
+				DEBUG_ERROR("boot-args size too large for BOOT_LINE_LENGTH, propDataSize=%zu\n", propDataSize);
+				ret = kIOReturnNoSpace;
+				goto exit;
+			}
+		}
+		break;
+
+	case kOFVariableTypeData:
+		propObject = OSDynamicPtrCast<OSData>(sharedObject);
+		if (propObject == nullptr) {
+			tmpString = OSDynamicCast(OSString, sharedObject.get());
+			if (tmpString != nullptr) {
+				propObject = OSData::withBytes(tmpString->getCStringNoCopy(),
+				    tmpString->getLength());
+			}
+		}
+
+		if (propObject != nullptr) {
+			propDataSize = (OSDynamicPtrCast<OSData>(propObject))->getLength();
+		}
+
+#if defined(XNU_TARGET_OS_OSX)
+		if ((propObject != nullptr) && ((OSDynamicPtrCast<OSData>(propObject))->getLength() == 0)) {
+			remove = true;
+		}
+#endif /* defined(XNU_TARGET_OS_OSX) */
+		break;
+	default:
+		break;
+	}
+
+	if (propObject == nullptr) {
+		DEBUG_INFO("No property object\n");
+		ret = kIOReturnBadArgument;
+		goto exit;
+	}
+
+	if (!verifyWriteSizeLimit(guid, name, propDataSize)) {
+		DEBUG_ERROR("Property data size of %zu too long for %s\n", propDataSize, name);
+		ret = kIOReturnNoSpace;
+		goto exit;
+	}
+
+	NVRAMWRITELOCK();
+	ok = handleSpecialVariables(name, guid, propObject.get(), &ret);
+	NVRAMUNLOCK();
+
+	if (ok) {
+		serializeVariables();
+		goto exit;
+	}
+
+	NVRAMREADLOCK();
+	oldObject.reset(dict->getObject(name), OSRetain);
+	NVRAMUNLOCK();
+
+	if (remove == false) {
+		DEBUG_INFO("Adding object\n");
+		NVRAMWRITELOCK();
+		if (!dict->setObject(name, propObject.get())) {
+			ret = kIOReturnBadArgument;
+		}
+		NVRAMUNLOCK();
+		if (_diags) {
+			UInt32 logSize = 0;
+			convertObjectToProp(nullptr, &logSize, name, propObject.get());
+			_diags->logVariable(getDictionaryType(dict), kIONVRAMOperationWrite, name, (void *)(uintptr_t)logSize);
+		}
+	} else {
+		DEBUG_INFO("Removing object\n");
+		// Check for existence so we can decide whether we need to sync variables
+		if (oldObject) {
+			ret = removePropertyWithGUIDAndName(guid, name);
+		} else {
+			ret = kIOReturnNotFound;
+		}
+	}
+
+	if (ret == kIOReturnSuccess) {
+		ret = serializeVariables();
+		if (ret != kIOReturnSuccess) {
+			DEBUG_ERROR("serializeVariables failed, ret=%#08x\n", ret);
+
+			NVRAMWRITELOCK();
+			if (oldObject) {
+				dict->setObject(name, oldObject.get());
+			} else {
+				dict->removeObject(name);
+			}
+			NVRAMUNLOCK();
+
+			(void) serializeVariables();
+			ret = kIOReturnNoSpace;
+		}
+	}
+
+	if (oldObject) {
+		oldObject.reset();
+	}
+	if (tmpString) {
+		propObject.reset();
+	}
+
+exit:
+	DEBUG_INFO("ret=%#08x\n", ret);
+
+	return ret;
+}
+
+IOReturn
+IODTNVRAM::setPropertyInternal(const OSSymbol *aKey, OSObject *anObject)
+{
+	const char            *variableName;
+	uuid_t                varGuid;
+
+	DEBUG_INFO("aKey=%s\n", aKey->getCStringNoCopy());
+
+	parseVariableName(aKey->getCStringNoCopy(), &varGuid, &variableName);
+
+	return setPropertyWithGUIDAndName(&varGuid, variableName, anObject);
+}
+
+bool
+IODTNVRAM::setProperty(const OSSymbol *aKey, OSObject *anObject)
+{
+	return setPropertyInternal(aKey, anObject) == kIOReturnSuccess;
+}
+
+void
+IODTNVRAM::removeProperty(const OSSymbol *aKey)
+{
+	IOReturn ret;
+
+	ret = removePropertyInternal(aKey);
+
+	if (ret == kIOReturnSuccess) {
+		serializeVariables();
+	} else {
+		DEBUG_INFO("removePropertyInternal failed, ret=%#08x\n", ret);
+	}
+}
+
+IOReturn
+IODTNVRAM::removePropertyWithGUIDAndName(const uuid_t *guid, const char *name)
+{
+	IOReturn     ret;
+	OSDictionary *dict;
+	bool removed = false;
+
+	DEBUG_INFO("name=%s\n", name);
+
+	ret = chooseDictionary(kIONVRAMOperationDelete, guid, name, &dict);
+	if (ret != kIOReturnSuccess) {
+		DEBUG_INFO("No dictionary\n");
+		goto exit;
+	}
+
+	if (!verifyPermission(kIONVRAMOperationDelete, guid, name)) {
+		DEBUG_INFO("Not priveleged\n");
+		ret = kIOReturnNotPrivileged;
+		goto exit;
+	}
+
+	NVRAMWRITELOCK();
+
+	// If the object exists, remove it from the dictionary.
+	if (dict->getObject(name) != nullptr) {
+		dict->removeObject(name);
+		removed = true;
+	} else {
+		DEBUG_INFO("%s not found\n", name);
+	}
+
+	NVRAMUNLOCK();
+
+	if (removed) {
+		if (_diags) {
+			_diags->logVariable(getDictionaryType(dict), kIONVRAMOperationDelete, name, nullptr);
+		}
+		ret = serializeVariables();
+		DEBUG_INFO("serializeVariables ret=0x%08x\n", ret);
+	}
+
+exit:
+	return ret;
+}
+
+IOReturn
+IODTNVRAM::removePropertyInternal(const OSSymbol *aKey)
+{
+	IOReturn     ret;
+	const char   *variableName;
+	uuid_t       varGuid;
+
+	DEBUG_INFO("aKey=%s\n", aKey->getCStringNoCopy());
+
+	parseVariableName(aKey->getCStringNoCopy(), &varGuid, &variableName);
+
+	ret = removePropertyWithGUIDAndName(&varGuid, variableName);
+
+	return ret;
+}
+
+IOReturn
+IODTNVRAM::setProperties(OSObject *properties)
+{
+	IOReturn                          ret = kIOReturnSuccess;
+	OSObject                          *object;
+	const OSSymbol                    *key;
+	OSDictionary                      *dict;
+	OSSharedPtr<OSCollectionIterator> iter;
+
+	dict = OSDynamicCast(OSDictionary, properties);
+	if (dict == nullptr) {
+		DEBUG_ERROR("Not a dictionary\n");
+		return kIOReturnBadArgument;
+	}
+
+	iter = OSCollectionIterator::withCollection(dict);
+	if (iter == nullptr) {
+		DEBUG_ERROR("Couldn't create iterator\n");
+		return kIOReturnBadArgument;
+	}
+
+	while (ret == kIOReturnSuccess) {
+		key = OSDynamicCast(OSSymbol, iter->getNextObject());
+		if (key == nullptr) {
+			break;
+		}
+
+		object = dict->getObject(key);
+		if (object == nullptr) {
+			continue;
+		}
+
+		ret = setPropertyInternal(key, object);
+	}
+
+	DEBUG_INFO("ret=%#08x\n", ret);
+
+	return ret;
+}
+
+IOReturn
+IODTNVRAM::readXPRAM(IOByteCount offset, UInt8 *buffer,
+    IOByteCount length)
+{
+	return kIOReturnUnsupported;
+}
+
+IOReturn
+IODTNVRAM::writeXPRAM(IOByteCount offset, UInt8 *buffer,
+    IOByteCount length)
+{
+	return kIOReturnUnsupported;
+}
+
+IOReturn
+IODTNVRAM::readNVRAMProperty(IORegistryEntry *entry,
+    const OSSymbol **name,
+    OSData **value)
+{
+	IOReturn err;
+
+	err = readNVRAMPropertyType1(entry, name, value);
+
+	return err;
+}
+
+IOReturn
+IODTNVRAM::writeNVRAMProperty(IORegistryEntry *entry,
+    const OSSymbol *name,
+    OSData *value)
+{
+	IOReturn err;
+
+	err = writeNVRAMPropertyType1(entry, name, value);
+
+	return err;
+}
+
+OSDictionary *
+IODTNVRAM::getNVRAMPartitions(void)
+{
+	return _nvramPartitionLengths.get();
+}
+
+IOReturn
+IODTNVRAM::readNVRAMPartition(const OSSymbol *partitionID,
+    IOByteCount offset, UInt8 *buffer,
+    IOByteCount length)
+{
+	OSNumber *partitionOffsetNumber, *partitionLengthNumber;
+	UInt32   partitionOffset, partitionLength, end;
+
+	partitionOffsetNumber =
+	    (OSNumber *)_nvramPartitionOffsets->getObject(partitionID);
+	partitionLengthNumber =
+	    (OSNumber *)_nvramPartitionLengths->getObject(partitionID);
+
+	if ((partitionOffsetNumber == nullptr) || (partitionLengthNumber == nullptr)) {
+		return kIOReturnNotFound;
+	}
+
+	partitionOffset = partitionOffsetNumber->unsigned32BitValue();
+	partitionLength = partitionLengthNumber->unsigned32BitValue();
+
+	if (os_add_overflow(offset, length, &end)) {
+		return kIOReturnBadArgument;
+	}
+	if ((buffer == nullptr) || (length == 0) || (end > partitionLength)) {
+		return kIOReturnBadArgument;
+	}
+
+	bcopy(_nvramImage + partitionOffset + offset, buffer, length);
+
+	return kIOReturnSuccess;
+}
+
+IOReturn
+IODTNVRAM::writeNVRAMPartition(const OSSymbol *partitionID,
+    IOByteCount offset, UInt8 *buffer,
+    IOByteCount length)
+{
+	OSNumber *partitionOffsetNumber, *partitionLengthNumber;
+	UInt32   partitionOffset, partitionLength, end;
+
+	partitionOffsetNumber =
+	    (OSNumber *)_nvramPartitionOffsets->getObject(partitionID);
+	partitionLengthNumber =
+	    (OSNumber *)_nvramPartitionLengths->getObject(partitionID);
+
+	if ((partitionOffsetNumber == nullptr) || (partitionLengthNumber == nullptr)) {
+		return kIOReturnNotFound;
+	}
+
+	partitionOffset = partitionOffsetNumber->unsigned32BitValue();
+	partitionLength = partitionLengthNumber->unsigned32BitValue();
+
+	if (os_add_overflow(offset, length, &end)) {
+		return kIOReturnBadArgument;
+	}
+	if ((buffer == nullptr) || (length == 0) || (end > partitionLength)) {
+		return kIOReturnBadArgument;
+	}
+
+	bcopy(buffer, _nvramImage + partitionOffset + offset, length);
+
+	if (_nvramController != nullptr) {
+		_nvramController->write(0, _nvramImage, _nvramSize);
+	}
+
+	return kIOReturnSuccess;
+}
+
+IOByteCount
+IODTNVRAM::savePanicInfo(UInt8 *buffer, IOByteCount length)
+{
+	return 0;
 }
 
 // Private methods
 
-UInt8 IODTNVRAM::calculatePartitionChecksum(UInt8 *partitionHeader)
-{
-  UInt8 cnt, isum, csum = 0;
-  
-  for (cnt = 0; cnt < 0x10; cnt++) {
-    isum = csum + partitionHeader[cnt];
-    if (isum < csum) isum++;
-    csum = isum;
-  }
-  
-  return csum;
-}
-
-struct OWVariablesHeader {
-  UInt16   owMagic;
-  UInt8    owVersion;
-  UInt8    owPages;
-  UInt16   owChecksum;
-  UInt16   owHere;
-  UInt16   owTop;
-  UInt16   owNext;
-  UInt32   owFlags;
-  UInt32   owNumbers[9];
-  struct {
-    UInt16 offset;
-    UInt16 length;
-  }        owStrings[10];
-};
-typedef struct OWVariablesHeader OWVariablesHeader;
-
-IOReturn IODTNVRAM::initOFVariables(void)
-{
-  UInt32            cnt, propOffset, propType;
-  UInt8             *propName, *propData;
-  UInt32            propNameLength, propDataLength;
-  const OSSymbol    *propSymbol;
-  OSObject          *propObject;
-  OWVariablesHeader *owHeader;
-
-  if (_ofImage == 0) return kIOReturnNotReady;
-  
-  _ofDict =  OSDictionary::withCapacity(1);
-  if (_ofDict == 0) return kIOReturnNoMemory;
-  
-  if (getPlatform()->getBootROMType()) {
-    cnt = 0;
-    while (cnt < _ofPartitionSize) {
-      // Break if there is no name.
-      if (_ofImage[cnt] == '\0') break;
-      
-      // Find the length of the name.
-      propName = _ofImage + cnt;
-      for (propNameLength = 0; (cnt + propNameLength) < _ofPartitionSize;
-	   propNameLength++) {
-	if (_ofImage[cnt + propNameLength] == '=') break;
-      }
-      
-      // Break if the name goes past the end of the partition.
-      if ((cnt + propNameLength) >= _ofPartitionSize) break;
-      cnt += propNameLength + 1;
-      
-      propData = _ofImage + cnt;
-      for (propDataLength = 0; (cnt + propDataLength) < _ofPartitionSize;
-	   propDataLength++) {
-	if (_ofImage[cnt + propDataLength] == '\0') break;
-      }
-      
-      // Break if the data goes past the end of the partition.
-      if ((cnt + propDataLength) >= _ofPartitionSize) break;
-      cnt += propDataLength + 1;
-      
-      if (convertPropToObject(propName, propNameLength,
-			      propData, propDataLength,
-			      &propSymbol, &propObject)) {
-	_ofDict->setObject(propSymbol, propObject);
-	propSymbol->release();
-	propObject->release();
-      }
-    }
-    
-    // Create the boot-args property if it is not in the dictionary.
-    if (_ofDict->getObject("boot-args") == 0) {
-      propObject = OSString::withCStringNoCopy("");
-      if (propObject != 0) {
-	_ofDict->setObject("boot-args", propObject);
-	propObject->release();
-      }
-    }
-    
-    // Create the 'aapl,panic-info' property if needed.
-    if (_piImage != 0) {
-      propDataLength = *(UInt32 *)_piImage;
-      if ((propDataLength != 0) && (propDataLength < (_piPartitionSize - 4))) {
-	propObject = OSData::withBytes(_piImage + 4, propDataLength);
-	_ofDict->setObject(kIODTNVRAMPanicInfoKey, propObject);
-	propObject->release();
-	
-	// Clear the length from _piImage and mark dirty.
-	*(UInt32 *)_piImage = 0;
-	_nvramImageDirty = true;
-      }
-    }
-  } else {
-    owHeader = (OWVariablesHeader *)_ofImage;
-    if (!validateOWChecksum(_ofImage)) {
-      _ofDict->release();
-      _ofDict = 0;
-      return kIOReturnBadMedia;
-    }
-    
-    cnt = 0;
-    while (1) {
-      if (!getOWVariableInfo(cnt++, &propSymbol, &propType, &propOffset))
+IOReturn
+IODTNVRAM::initVariables(void)
+{
+	UInt32                      cnt, cntStart;
+	const UInt8                 *propName, *propData;
+	UInt32                      propNameLength, propDataLength, regionIndex;
+	OSSharedPtr<const OSSymbol> propSymbol;
+	OSSharedPtr<OSObject>       propObject;
+	NVRAMRegionInfo             *currentRegion;
+	NVRAMRegionInfo             variableRegions[] = { { kIONVRAMPartitionCommon, _commonPartitionOffset, _commonPartitionSize, _commonDict},
+							  { kIONVRAMPartitionSystem, _systemPartitionOffset, _systemPartitionSize, _systemDict} };
+
+	DEBUG_INFO("...\n");
+
+	for (regionIndex = 0; regionIndex < ARRAY_SIZE(variableRegions); regionIndex++) {
+		currentRegion = &variableRegions[regionIndex];
+		const uint8_t * imageData = _nvramImage + currentRegion->offset;
+
+		if (currentRegion->size == 0) {
+			continue;
+		}
+
+		currentRegion->dict = OSDictionary::withCapacity(1);
+
+		DEBUG_INFO("region = %d\n", currentRegion->type);
+		cnt = 0;
+		while (cnt < currentRegion->size) {
+			cntStart = cnt;
+			// Break if there is no name.
+			if (imageData[cnt] == '\0') {
+				break;
+			}
+
+			// Find the length of the name.
+			propName = imageData + cnt;
+			for (propNameLength = 0; (cnt + propNameLength) < currentRegion->size;
+			    propNameLength++) {
+				if (imageData[cnt + propNameLength] == '=') {
+					break;
+				}
+			}
+
+			// Break if the name goes past the end of the partition.
+			if ((cnt + propNameLength) >= currentRegion->size) {
+				break;
+			}
+			cnt += propNameLength + 1;
+
+			propData = imageData + cnt;
+			for (propDataLength = 0; (cnt + propDataLength) < currentRegion->size;
+			    propDataLength++) {
+				if (imageData[cnt + propDataLength] == '\0') {
+					break;
+				}
+			}
+
+			// Break if the data goes past the end of the partition.
+			if ((cnt + propDataLength) >= currentRegion->size) {
+				break;
+			}
+			cnt += propDataLength + 1;
+
+			if (convertPropToObject(propName, propNameLength,
+			    propData, propDataLength,
+			    propSymbol, propObject)) {
+				DEBUG_INFO("adding %s, dataLength=%u\n", propSymbol.get()->getCStringNoCopy(), (unsigned int)propDataLength);
+				currentRegion->dict.get()->setObject(propSymbol.get(), propObject.get());
+				if (_diags) {
+					_diags->logVariable(getDictionaryType(currentRegion->dict.get()), kIONVRAMOperationInit, propSymbol.get()->getCStringNoCopy(), (void *)(uintptr_t)(cnt - cntStart));
+				}
+			}
+		}
+	}
+
+	// Create the boot-args property if it is not in the dictionary.
+	if (_systemDict != nullptr) {
+		if (_systemDict->getObject(kIONVRAMBootArgsKey) == nullptr) {
+			propObject = OSString::withCStringNoCopy("");
+			if (propObject != nullptr) {
+				_systemDict->setObject(kIONVRAMBootArgsKey, propObject.get());
+			}
+		}
+	} else if (_commonDict != nullptr) {
+		if (_commonDict->getObject(kIONVRAMBootArgsKey) == nullptr) {
+			propObject = OSString::withCStringNoCopy("");
+			if (propObject != nullptr) {
+				_commonDict->setObject(kIONVRAMBootArgsKey, propObject.get());
+			}
+		}
+	}
+
+	DEBUG_INFO("%s _commonDict=%p _systemDict=%p\n", __FUNCTION__, _commonDict ? _commonDict.get() : nullptr, _systemDict ? _systemDict.get() : nullptr);
+
+	return kIOReturnSuccess;
+}
+
+IOReturn
+IODTNVRAM::serializeVariables(void)
+{
+	IOReturn                          ret;
+	bool                              ok = false;
+	UInt32                            length, maxLength, regionIndex;
+	UInt8                             *buffer, *tmpBuffer;
+	const OSSymbol                    *tmpSymbol;
+	OSObject                          *tmpObject;
+	OSSharedPtr<OSCollectionIterator> iter;
+	OSSharedPtr<OSNumber>             sizeUsed;
+	OSSharedPtr<OSNumber>             generation;
+	UInt32                            systemUsed = 0;
+	UInt32                            commonUsed = 0;
+	UInt8                             *nvramImage;
+	NVRAMRegionInfo                   *currentRegion;
+	NVRAMRegionInfo                   variableRegions[] = { { kIONVRAMPartitionCommon, _commonPartitionOffset, _commonPartitionSize, _commonDict},
+								{ kIONVRAMPartitionSystem, _systemPartitionOffset, _systemPartitionSize, _systemDict} };
+
+	require_action(_systemPanicked == false, exit, ret = kIOReturnNotReady);
+
+	require_action(_nvramController != nullptr, exit, (ret = kIOReturnNotReady, DEBUG_ERROR("No _nvramController\n")));
+
+	nvramImage = IONewZeroData(UInt8, _nvramSize);
+	require_action(nvramImage != nullptr, exit, (ret = kIOReturnNoMemory, DEBUG_ERROR("Can't create NVRAM image copy\n")));
+
+	DEBUG_INFO("...\n");
+
+	// Lock here to synchronize with possible sync() call contention
+	// when updating header
+	CONTROLLERLOCK();
+	bcopy(_nvramImage, nvramImage, _nvramSize);
+	CONTROLLERUNLOCK();
+
+	NVRAMREADLOCK();
+
+	for (regionIndex = 0; regionIndex < ARRAY_SIZE(variableRegions); regionIndex++) {
+		currentRegion = &variableRegions[regionIndex];
+
+		if (currentRegion->size == 0) {
+			continue;
+		}
+
+		DEBUG_INFO("region = %d\n", currentRegion->type);
+		buffer = tmpBuffer = nvramImage + currentRegion->offset;
+
+		bzero(buffer, currentRegion->size);
+
+		ok = true;
+		maxLength = currentRegion->size;
+
+		iter = OSCollectionIterator::withCollection(currentRegion->dict.get());
+		if (iter == nullptr) {
+			ok = false;
+		}
+
+		while (ok) {
+			tmpSymbol = OSDynamicCast(OSSymbol, iter->getNextObject());
+			if (tmpSymbol == nullptr) {
+				break;
+			}
+
+			DEBUG_INFO("adding variable %s\n", tmpSymbol->getCStringNoCopy());
+
+			tmpObject = currentRegion->dict->getObject(tmpSymbol);
+
+			length = maxLength;
+			ok = convertObjectToProp(tmpBuffer, &length, tmpSymbol, tmpObject);
+			if (ok) {
+				tmpBuffer += length;
+				maxLength -= length;
+			}
+		}
+
+		if (!ok) {
+			ret = kIOReturnNoSpace;
+			IODeleteData(nvramImage, UInt8, _nvramSize);
+			break;
+		}
+
+		if ((currentRegion->type == kIONVRAMPartitionSystem) &&
+		    (_systemService != nullptr)) {
+			_systemService->setVariables(_systemDict.get());
+			systemUsed = (uint32_t)(tmpBuffer - buffer);
+		} else if ((currentRegion->type == kIONVRAMPartitionCommon) &&
+		    (_commonService != nullptr)) {
+			_commonService->setVariables(_commonDict.get());
+			commonUsed = (uint32_t)(tmpBuffer - buffer);
+		}
+	}
+
+	NVRAMUNLOCK();
+
+	DEBUG_INFO("ok=%d\n", ok);
+	require(ok, exit);
+
+	CONTROLLERLOCK();
+
+	if (_systemService && _diags) {
+		sizeUsed = OSNumber::withNumber(systemUsed, 32);
+		_diags->setProperty("SystemUsed", sizeUsed.get());
+		DEBUG_INFO("SystemUsed=%u\n", (unsigned int)systemUsed);
+		sizeUsed.reset();
+	}
+
+	if (_commonService && _diags) {
+		sizeUsed = OSNumber::withNumber(commonUsed, 32);
+		_diags->setProperty("CommonUsed", sizeUsed.get());
+		DEBUG_INFO("CommonUsed=%u\n", (unsigned int)commonUsed);
+		sizeUsed.reset();
+	}
+
+	nvram_set_apple_header(nvramImage, _nvramSize, _nvramGeneration, _nvramVersion);
+
+	ret = _nvramController->write(0, nvramImage, _nvramSize);
+
+	if (_diags) {
+		generation = OSNumber::withNumber(_nvramGeneration, 32);
+		_diags->setProperty(kCurrentGenerationCountKey, generation.get());
+	}
+
+	if (_nvramImage) {
+		IODeleteData(_nvramImage, UInt8, _nvramSize);
+	}
+
+	_nvramImage = nvramImage;
+
+	CONTROLLERUNLOCK();
+
+exit:
+	return ret;
+}
+
+bool
+IODTNVRAM::convertPropToObject(const UInt8 *propName, UInt32 propNameLength,
+    const UInt8 *propData, UInt32 propDataLength,
+    const OSSymbol **propSymbol,
+    OSObject **propObject)
+{
+	OSSharedPtr<const OSString> delimitedName;
+	OSSharedPtr<const OSSymbol> tmpSymbol;
+	OSSharedPtr<OSNumber>       tmpNumber;
+	OSSharedPtr<OSString>       tmpString;
+	OSSharedPtr<OSObject>       tmpObject = nullptr;
+
+	delimitedName = OSString::withCString((const char *)propName, propNameLength);
+	tmpSymbol = OSSymbol::withString(delimitedName.get());
+
+	if (tmpSymbol == nullptr) {
+		return false;
+	}
+
+	switch (getVariableType(tmpSymbol.get())) {
+	case kOFVariableTypeBoolean:
+		if (!strncmp("true", (const char *)propData, propDataLength)) {
+			tmpObject.reset(kOSBooleanTrue, OSRetain);
+		} else if (!strncmp("false", (const char *)propData, propDataLength)) {
+			tmpObject.reset(kOSBooleanFalse, OSRetain);
+		}
+		break;
+
+	case kOFVariableTypeNumber:
+		tmpNumber = OSNumber::withNumber(strtol((const char *)propData, nullptr, 0), 32);
+		if (tmpNumber != nullptr) {
+			tmpObject = tmpNumber;
+		}
+		break;
+
+	case kOFVariableTypeString:
+		tmpString = OSString::withCString((const char *)propData, propDataLength);
+		if (tmpString != nullptr) {
+			tmpObject = tmpString;
+		}
+		break;
+
+	case kOFVariableTypeData:
+		tmpObject = unescapeBytesToData(propData, propDataLength);
+		break;
+
+	default:
+		break;
+	}
+
+	if (tmpObject == nullptr) {
+		tmpSymbol.reset();
+		return false;
+	}
+
+	*propSymbol = tmpSymbol.detach();
+	*propObject = tmpObject.detach();
+
+	return true;
+}
+
+bool
+IODTNVRAM::convertPropToObject(const UInt8 *propName, UInt32 propNameLength,
+    const UInt8 *propData, UInt32 propDataLength,
+    OSSharedPtr<const OSSymbol>& propSymbol,
+    OSSharedPtr<OSObject>& propObject)
+{
+	const OSSymbol* propSymbolRaw = nullptr;
+	OSObject* propObjectRaw = nullptr;
+	bool ok = convertPropToObject(propName, propNameLength, propData, propDataLength,
+	    &propSymbolRaw, &propObjectRaw);
+	propSymbol.reset(propSymbolRaw, OSNoRetain);
+	propObject.reset(propObjectRaw, OSNoRetain);
+	return ok;
+}
+
+bool
+IODTNVRAM::convertObjectToProp(UInt8 *buffer, UInt32 *length,
+    const OSSymbol *propSymbol, OSObject *propObject)
+{
+	return convertObjectToProp(buffer, length, propSymbol->getCStringNoCopy(), propObject);
+}
+
+bool
+IODTNVRAM::convertObjectToProp(UInt8 *buffer, UInt32 *length,
+    const char *propName, OSObject *propObject)
+{
+	UInt32               propNameLength, propDataLength, remaining, offset;
+	IONVRAMVariableType  propType;
+	OSBoolean            *tmpBoolean = nullptr;
+	OSNumber             *tmpNumber = nullptr;
+	OSString             *tmpString = nullptr;
+	OSSharedPtr<OSData>  tmpData;
+
+	propNameLength = (UInt32)strlen(propName);
+	propType = getVariableType(propName);
+	offset = 0;
+	remaining = 0;
+
+	// Get the size of the data.
+	propDataLength = 0xFFFFFFFF;
+	switch (propType) {
+	case kOFVariableTypeBoolean:
+		tmpBoolean = OSDynamicCast(OSBoolean, propObject);
+		if (tmpBoolean != nullptr) {
+			propDataLength = 5;
+		}
+		break;
+
+	case kOFVariableTypeNumber:
+		tmpNumber = OSDynamicCast(OSNumber, propObject);
+		if (tmpNumber != nullptr) {
+			propDataLength = 10;
+		}
+		break;
+
+	case kOFVariableTypeString:
+		tmpString = OSDynamicCast(OSString, propObject);
+		if (tmpString != nullptr) {
+			propDataLength = tmpString->getLength();
+		}
+		break;
+
+	case kOFVariableTypeData:
+		tmpData.reset(OSDynamicCast(OSData, propObject), OSNoRetain);
+		if (tmpData != nullptr) {
+			tmpData = escapeDataToData(tmpData.detach());
+			// escapeDataToData() adds the NULL byte to the data
+			// subtract 1 here to keep offset consistent with the other cases
+			propDataLength = tmpData->getLength() - 1;
+		}
+		break;
+
+	default:
+		break;
+	}
+
+	// Make sure the propertySize is known and will fit.
+	if (propDataLength == 0xFFFFFFFF) {
+		return false;
+	}
+
+	if (buffer) {
+		// name + '=' + data + '\0'
+		if ((propNameLength + propDataLength + 2) > *length) {
+			return false;
+		}
+
+		remaining = *length;
+	}
+
+	*length = 0;
+
+	// Copy the property name equal sign.
+	offset += snprintf((char *)buffer, remaining, "%s=", propName);
+	if (buffer) {
+		if (remaining > offset) {
+			buffer += offset;
+			remaining = remaining - offset;
+		} else {
+			return false;
+		}
+	}
+
+	switch (propType) {
+	case kOFVariableTypeBoolean:
+		if (tmpBoolean->getValue()) {
+			offset += strlcpy((char *)buffer, "true", remaining);
+		} else {
+			offset += strlcpy((char *)buffer, "false", remaining);
+		}
+		break;
+
+	case kOFVariableTypeNumber:
+	{
+		uint32_t tmpValue = tmpNumber->unsigned32BitValue();
+		if (tmpValue == 0xFFFFFFFF) {
+			offset += strlcpy((char *)buffer, "-1", remaining);
+		} else if (tmpValue < 1000) {
+			offset += snprintf((char *)buffer, remaining, "%d", (uint32_t)tmpValue);
+		} else {
+			offset += snprintf((char *)buffer, remaining, "%#x", (uint32_t)tmpValue);
+		}
+	}
 	break;
-      
-      switch (propType) {
-      case kOFVariableTypeBoolean :
-	propObject = OSBoolean::withBoolean(owHeader->owFlags & propOffset);
-	break;
-	
-      case kOFVariableTypeNumber :
-	propObject = OSNumber::withNumber(owHeader->owNumbers[propOffset], 32);
-	break;
-	
-      case kOFVariableTypeString :
-	propData = _ofImage + owHeader->owStrings[propOffset].offset -
-	  _ofPartitionOffset;
-	propDataLength = owHeader->owStrings[propOffset].length;
-	propName = IONew(UInt8, propDataLength + 1);
-	if (propName != 0) {
-	  strncpy((char *)propName, (const char *)propData, propDataLength);
-	  propName[propDataLength] = '\0';
-	  propObject = OSString::withCString((const char *)propName);
-	  IODelete(propName, UInt8, propDataLength + 1);
-	}
-	break;
-      }
-      
-      if (propObject == 0) break;
-      
-      _ofDict->setObject(propSymbol, propObject);
-      propSymbol->release();
-      propObject->release();
-    }
-    
-    // Create the boot-args property.
-    propSymbol = OSSymbol::withCString("boot-command");
-    if (propSymbol != 0) {
-      propObject = _ofDict->getObject(propSymbol);
-      if (propObject != 0) {
-	updateOWBootArgs(propSymbol, propObject);
-      }
-      propSymbol->release();
-    }
-  }
-  
-  return kIOReturnSuccess;
-}
-
-IOReturn IODTNVRAM::syncOFVariables(void)
-{
-  bool                 ok;
-  UInt32               cnt, length, maxLength;
-  UInt32               curOffset, tmpOffset, tmpType, tmpDataLength;
-  UInt8                *buffer, *tmpBuffer, *tmpData;
-  const OSSymbol       *tmpSymbol;
-  OSObject             *tmpObject;
-  OSBoolean            *tmpBoolean;
-  OSNumber             *tmpNumber;
-  OSString             *tmpString;
-  OSCollectionIterator *iter;
-  OWVariablesHeader    *owHeader, *owHeaderOld;
-  
-  if ((_ofImage == 0) || (_ofDict == 0)) return kIOReturnNotReady;
-  
-  if (!_ofImageDirty) return kIOReturnSuccess;
-  
-  if (getPlatform()->getBootROMType()) {
-    buffer = tmpBuffer = IONew(UInt8, _ofPartitionSize);
-    if (buffer == 0) return kIOReturnNoMemory;
-    bzero(buffer, _ofPartitionSize);
-    
-    ok = true;
-    maxLength = _ofPartitionSize;
-    
-    iter = OSCollectionIterator::withCollection(_ofDict);
-    if (iter == 0) ok = false;
-    
-    while (ok) {
-      tmpSymbol = OSDynamicCast(OSSymbol, iter->getNextObject());
-      if (tmpSymbol == 0) break;
-      
-      // Don't save 'aapl,panic-info'.
-      if (tmpSymbol->isEqualTo(kIODTNVRAMPanicInfoKey)) continue;
-      
-      tmpObject = _ofDict->getObject(tmpSymbol);
-      
-      length = maxLength;
-      ok = convertObjectToProp(tmpBuffer, &length, tmpSymbol, tmpObject);
-      if (ok) {
-	tmpBuffer += length;
-	maxLength -= length;
-      }
-    }
-    iter->release();
-    
-    if (ok) {
-      bcopy(buffer, _ofImage, _ofPartitionSize);
-    }
-    
-    IODelete(buffer, UInt8, _ofPartitionSize);
-    
-    if (!ok) return kIOReturnBadArgument;
-  } else {
-    buffer = IONew(UInt8, _ofPartitionSize);
-    if (buffer == 0) return kIOReturnNoMemory;
-    bzero(buffer, _ofPartitionSize);
-    
-    owHeader    = (OWVariablesHeader *)buffer;
-    owHeaderOld = (OWVariablesHeader *)_ofImage;
-    
-    owHeader->owMagic = owHeaderOld->owMagic;
-    owHeader->owVersion = owHeaderOld->owVersion;
-    owHeader->owPages = owHeaderOld->owPages;
-    
-    curOffset = _ofPartitionSize;
-    
-    ok = true;
-    cnt = 0;
-    while (ok) {
-      if (!getOWVariableInfo(cnt++, &tmpSymbol, &tmpType, &tmpOffset))
-	break;
-      
-      tmpObject = _ofDict->getObject(tmpSymbol);
-      
-      switch (tmpType) {
-      case kOFVariableTypeBoolean :
-	tmpBoolean = OSDynamicCast(OSBoolean, tmpObject);
-	if (tmpBoolean->getValue()) owHeader->owFlags |= tmpOffset;
-	break;
-	
-      case kOFVariableTypeNumber :
-	tmpNumber = OSDynamicCast(OSNumber, tmpObject);
-	owHeader->owNumbers[tmpOffset] = tmpNumber->unsigned32BitValue();
-        break;
-	
-      case kOFVariableTypeString :
-	tmpString = OSDynamicCast(OSString, tmpObject);
-	tmpData = (UInt8 *) tmpString->getCStringNoCopy();
-	tmpDataLength = tmpString->getLength();
-	
-	if ((curOffset - tmpDataLength) < sizeof(OWVariablesHeader)) {
-	  ok = false;
-	  break;
-	}
-	
-	owHeader->owStrings[tmpOffset].length = tmpDataLength;
-	curOffset -= tmpDataLength;
-	owHeader->owStrings[tmpOffset].offset = curOffset + _ofPartitionOffset;
-	if (tmpDataLength != 0)
-	  bcopy(tmpData, buffer + curOffset, tmpDataLength);
-	break;
-      }
-    }
-    
-    if (ok) {
-      owHeader->owHere = _ofPartitionOffset + sizeof(OWVariablesHeader);
-      owHeader->owTop = _ofPartitionOffset + curOffset;
-      owHeader->owNext = 0;
-      
-      owHeader->owChecksum = 0;
-      owHeader->owChecksum = ~generateOWChecksum(buffer);
-      
-      bcopy(buffer, _ofImage, _ofPartitionSize);
-    }
-    
-    IODelete(buffer, UInt8, _ofPartitionSize);
-    
-    if (!ok) return kIOReturnBadArgument;
-  }
-  
-  _ofImageDirty = false;
-  _nvramImageDirty = true;
-  
-  return kIOReturnSuccess;
-}
-
-struct OFVariable {
-  char   *variableName;
-  UInt32 variableType;
-  UInt32 variablePerm;
-  SInt32 variableOffset;
-};
-typedef struct OFVariable OFVariable;
-
-enum {
-  kOWVariableOffsetNumber = 8,
-  kOWVariableOffsetString = 17
-};
-
-OFVariable gOFVariables[] = {
-  {"little-endian?", kOFVariableTypeBoolean, kOFVariablePermUserRead, 0},
-  {"real-mode?", kOFVariableTypeBoolean, kOFVariablePermUserRead, 1},
-  {"auto-boot?", kOFVariableTypeBoolean, kOFVariablePermUserRead, 2},
-  {"diag-switch?", kOFVariableTypeBoolean, kOFVariablePermUserRead, 3},
-  {"fcode-debug?", kOFVariableTypeBoolean, kOFVariablePermUserRead, 4},
-  {"oem-banner?", kOFVariableTypeBoolean, kOFVariablePermUserRead, 5},
-  {"oem-logo?", kOFVariableTypeBoolean, kOFVariablePermUserRead, 6},
-  {"use-nvramrc?", kOFVariableTypeBoolean, kOFVariablePermUserRead, 7},
-  {"use-generic?", kOFVariableTypeBoolean, kOFVariablePermUserRead, -1},
-  {"default-mac-address?", kOFVariableTypeBoolean, kOFVariablePermUserRead,-1},
-  {"real-base", kOFVariableTypeNumber, kOFVariablePermUserRead, 8},
-  {"real-size", kOFVariableTypeNumber, kOFVariablePermUserRead, 9},
-  {"virt-base", kOFVariableTypeNumber, kOFVariablePermUserRead, 10},
-  {"virt-size", kOFVariableTypeNumber, kOFVariablePermUserRead, 11},
-  {"load-base", kOFVariableTypeNumber, kOFVariablePermUserRead, 12},
-  {"pci-probe-list", kOFVariableTypeNumber, kOFVariablePermUserRead, 13},
-  {"pci-probe-mask", kOFVariableTypeNumber, kOFVariablePermUserRead, -1},
-  {"screen-#columns", kOFVariableTypeNumber, kOFVariablePermUserRead, 14},
-  {"screen-#rows", kOFVariableTypeNumber, kOFVariablePermUserRead, 15},
-  {"selftest-#megs", kOFVariableTypeNumber, kOFVariablePermUserRead, 16},
-  {"boot-device", kOFVariableTypeString, kOFVariablePermUserRead, 17},
-  {"boot-file", kOFVariableTypeString, kOFVariablePermUserRead, 18},
-  {"boot-screen", kOFVariableTypeString, kOFVariablePermUserRead, -1},
-  {"console-screen", kOFVariableTypeString, kOFVariablePermUserRead, -1},
-  {"diag-device", kOFVariableTypeString, kOFVariablePermUserRead, 19},
-  {"diag-file", kOFVariableTypeString, kOFVariablePermUserRead, 20},
-  {"input-device", kOFVariableTypeString, kOFVariablePermUserRead, 21},
-  {"output-device", kOFVariableTypeString, kOFVariablePermUserRead, 22},
-  {"input-device-1", kOFVariableTypeString, kOFVariablePermUserRead, -1},
-  {"output-device-1", kOFVariableTypeString, kOFVariablePermUserRead, -1},
-  {"mouse-device", kOFVariableTypeString, kOFVariablePermUserRead, -1},
-  {"oem-banner", kOFVariableTypeString, kOFVariablePermUserRead, 23},
-  {"oem-logo", kOFVariableTypeString, kOFVariablePermUserRead, 24},
-  {"nvramrc", kOFVariableTypeString, kOFVariablePermUserRead, 25},
-  {"boot-command", kOFVariableTypeString, kOFVariablePermUserRead, 26},
-  {"default-client-ip", kOFVariableTypeString, kOFVariablePermUserRead, -1},
-  {"default-server-ip", kOFVariableTypeString, kOFVariablePermUserRead, -1},
-  {"default-gateway-ip", kOFVariableTypeString, kOFVariablePermUserRead, -1},
-  {"default-subnet-mask", kOFVariableTypeString, kOFVariablePermUserRead, -1},
-  {"default-router-ip", kOFVariableTypeString, kOFVariablePermUserRead, -1},
-  {"boot-script", kOFVariableTypeString, kOFVariablePermUserRead, -1},
-  {"boot-args", kOFVariableTypeString, kOFVariablePermUserRead, -1},
-  {"aapl,pci", kOFVariableTypeData, kOFVariablePermRootOnly, -1},
-  {"security-mode", kOFVariableTypeString, kOFVariablePermUserRead, -1},
-  {"security-password", kOFVariableTypeData, kOFVariablePermRootOnly, -1},
-  {0, kOFVariableTypeData, kOFVariablePermUserRead, -1}
-};
-
-UInt32 IODTNVRAM::getOFVariableType(const OSSymbol *propSymbol) const
-{
-  OFVariable *ofVar;
-  
-  ofVar = gOFVariables;
-  while (1) {
-    if ((ofVar->variableName == 0) ||
-	propSymbol->isEqualTo(ofVar->variableName)) break;
-    ofVar++;
-  }
-  
-  return ofVar->variableType;
-}
-
-UInt32 IODTNVRAM::getOFVariablePerm(const OSSymbol *propSymbol) const
-{
-  OFVariable *ofVar;
-  
-  ofVar = gOFVariables;
-  while (1) {
-    if ((ofVar->variableName == 0) ||
-	propSymbol->isEqualTo(ofVar->variableName)) break;
-    ofVar++;
-  }
-  
-  return ofVar->variablePerm;
-}
-
-bool IODTNVRAM::getOWVariableInfo(UInt32 variableNumber, const OSSymbol **propSymbol,
-				  UInt32 *propType, UInt32 *propOffset)
-{
-  OFVariable *ofVar;
-  
-  ofVar = gOFVariables;
-  while (1) {
-    if (ofVar->variableName == 0) return false;
-    
-    if (ofVar->variableOffset == (SInt32) variableNumber) break;
-    
-    ofVar++;
-  }
-  
-  *propSymbol = OSSymbol::withCStringNoCopy(ofVar->variableName);
-  *propType = ofVar->variableType;
-  
-  switch (*propType) {
-  case kOFVariableTypeBoolean :
-    *propOffset = 1 << (31 - variableNumber);
-    break;
-    
-  case kOFVariableTypeNumber :
-    *propOffset = variableNumber - kOWVariableOffsetNumber;
-    break;
-    
-  case kOFVariableTypeString :
-    *propOffset = variableNumber - kOWVariableOffsetString;
-    break;
-  }
-  
-  return true;
-}
-
-bool IODTNVRAM::convertPropToObject(UInt8 *propName, UInt32 propNameLength,
-				    UInt8 *propData, UInt32 propDataLength,
-				    const OSSymbol **propSymbol,
-				    OSObject **propObject)
-{
-  UInt32         propType;
-  const OSSymbol *tmpSymbol;
-  OSObject       *tmpObject;
-  OSNumber       *tmpNumber;
-  OSString       *tmpString;
-  
-  // Create the symbol.
-  propName[propNameLength] = '\0';
-  tmpSymbol = OSSymbol::withCString((const char *)propName);
-  propName[propNameLength] = '=';
-  if (tmpSymbol == 0) {
-    return false;
-  }
-  
-  propType = getOFVariableType(tmpSymbol);
-  
-  // Create the object.
-  tmpObject = 0;
-  switch (propType) {
-  case kOFVariableTypeBoolean :
-    if (!strncmp("true", (const char *)propData, propDataLength)) {
-      tmpObject = kOSBooleanTrue;
-    } else if (!strncmp("false", (const char *)propData, propDataLength)) {
-      tmpObject = kOSBooleanFalse;
-    }
-    break;
-    
-  case kOFVariableTypeNumber :
-    tmpNumber = OSNumber::withNumber(strtol((const char *)propData, 0, 0), 32);
-    if (tmpNumber != 0) tmpObject = tmpNumber;
-    break;
-    
-  case kOFVariableTypeString :
-    tmpString = OSString::withCString((const char *)propData);
-    if (tmpString != 0) tmpObject = tmpString;
-    break;
-    
-  case kOFVariableTypeData :
-    tmpObject = unescapeBytesToData(propData, propDataLength);
-    break;
-  }
-  
-  if (tmpObject == 0) {
-    tmpSymbol->release();
-    return false;
-  }
-  
-  *propSymbol = tmpSymbol;
-  *propObject = tmpObject;
-  
-  return true;
-}
-
-bool IODTNVRAM::convertObjectToProp(UInt8 *buffer, UInt32 *length,
-				    const OSSymbol *propSymbol, OSObject *propObject)
-{
-  UInt8          *propName;
-  UInt32         propNameLength, propDataLength;
-  UInt32         propType, tmpValue;
-  OSBoolean      *tmpBoolean = 0;
-  OSNumber       *tmpNumber = 0;
-  OSString       *tmpString = 0;
-  OSData         *tmpData = 0;
-  
-  propName = (UInt8 *)propSymbol->getCStringNoCopy();
-  propNameLength = propSymbol->getLength();
-  propType = getOFVariableType(propSymbol);
-  
-  // Get the size of the data.
-  propDataLength = 0xFFFFFFFF;
-  switch (propType) {
-  case kOFVariableTypeBoolean :
-    tmpBoolean = OSDynamicCast(OSBoolean, propObject);
-    if (tmpBoolean != 0) propDataLength = 5;
-    break;
-    
-  case kOFVariableTypeNumber :
-    tmpNumber = OSDynamicCast(OSNumber, propObject);
-    if (tmpNumber != 0) propDataLength = 10;
-    break;
-    
-  case kOFVariableTypeString :
-    tmpString = OSDynamicCast(OSString, propObject);
-    if (tmpString != 0) propDataLength = tmpString->getLength();
-    break;
-    
-  case kOFVariableTypeData :
-    tmpData = OSDynamicCast(OSData, propObject); 
-    if (tmpData != 0) {
-      tmpData = escapeDataToData(tmpData);
-      propDataLength = tmpData->getLength();
-    }
-    break;
-  }
-  
-  // Make sure the propertySize is known and will fit.
-  if (propDataLength == 0xFFFFFFFF) return false;
-  if ((propNameLength + propDataLength + 2) > *length) return false;
-  
-  // Copy the property name equal sign.
-  sprintf((char *)buffer, "%s=", propName);
-  buffer += propNameLength + 1;
-  
-  switch (propType) {
-  case kOFVariableTypeBoolean :
-    if (tmpBoolean->getValue()) {
-      strcpy((char *)buffer, "true");
-    } else {
-      strcpy((char *)buffer, "false");
-    }
-    break;
-    
-  case kOFVariableTypeNumber :
-    tmpValue = tmpNumber->unsigned32BitValue();
-    if (tmpValue == 0xFFFFFFFF) {
-      strcpy((char *)buffer, "-1");
-    } else if (tmpValue < 1000) {
-      sprintf((char *)buffer, "%ld", tmpValue);
-    } else {
-      sprintf((char *)buffer, "0x%lx", tmpValue);
-    }
-    break;
-    
-  case kOFVariableTypeString :
-    strcpy((char *)buffer, tmpString->getCStringNoCopy());
-    break;
-    
-  case kOFVariableTypeData :
-    bcopy(tmpData->getBytesNoCopy(), buffer, propDataLength);
-    tmpData->release();
-    break;
-  }
-  
-  propDataLength = strlen((const char *)buffer);  
-  
-  *length = propNameLength + propDataLength + 2;
-  
-  return true;
-}
-
-
-UInt16 IODTNVRAM::generateOWChecksum(UInt8 *buffer)
-{
-  UInt32 cnt, checksum = 0;
-  UInt16 *tmpBuffer = (UInt16 *)buffer;
-  
-  for (cnt = 0; cnt < _ofPartitionSize / 2; cnt++)
-    checksum += tmpBuffer[cnt];
-  
-  return checksum % 0x0000FFFF;
-}
-
-bool IODTNVRAM::validateOWChecksum(UInt8 *buffer)
-{
-  UInt32 cnt, checksum, sum = 0;
-  UInt16 *tmpBuffer = (UInt16 *)buffer;
-  
-  for (cnt = 0; cnt < _ofPartitionSize / 2; cnt++)
-    sum += tmpBuffer[cnt];
-  
-  checksum = (sum >> 16) + (sum & 0x0000FFFF);
-  if (checksum == 0x10000) checksum--;
-  checksum = (checksum ^ 0x0000FFFF) & 0x0000FFFF;
-  
-  return checksum == 0;
-}
-
-void IODTNVRAM::updateOWBootArgs(const OSSymbol *key, OSObject *value)
-{
-  bool     wasBootArgs, bootr = false;
-  UInt32   cnt;
-  OSString *tmpString, *bootCommand, *bootArgs = 0;
-  UInt8    *bootCommandData, *bootArgsData, *tmpData;
-  UInt32   bootCommandDataLength, bootArgsDataLength, tmpDataLength;
-  
-  tmpString = OSDynamicCast(OSString, value);
-  if (tmpString == 0) return;
-  
-  if (key->isEqualTo("boot-command")) {
-    wasBootArgs = false;
-    bootCommand = tmpString;
-  } else if (key->isEqualTo("boot-args")) {
-    wasBootArgs = true;
-    bootArgs = tmpString;
-    bootCommand = OSDynamicCast(OSString, _ofDict->getObject("boot-command"));
-    if (bootCommand == 0) return;
-  } else return;
-  
-  bootCommandData = (UInt8 *)bootCommand->getCStringNoCopy();
-  bootCommandDataLength = bootCommand->getLength();
-  
-  if (bootCommandData == 0) return;
-  
-  for (cnt = 0; cnt < bootCommandDataLength; cnt++) {
-    if ((bootCommandData[cnt] == 'b') &&
-	!strncmp("bootr", (const char *)bootCommandData + cnt, 5)) {
-      cnt += 5;
-      while (bootCommandData[cnt] == ' ') cnt++;
-      bootr = true;
-      break;
-    }
-  }
-  if (!bootr) {
-    _ofDict->removeObject("boot-args");
-    return;
-  }
-  
-  if (wasBootArgs) {
-    bootArgsData = (UInt8 *)bootArgs->getCStringNoCopy();
-    bootArgsDataLength = bootArgs->getLength();
-    if (bootArgsData == 0) return;
-    
-    tmpDataLength = cnt + bootArgsDataLength;
-    tmpData = IONew(UInt8, tmpDataLength + 1);
-    if (tmpData == 0) return;
-    
-    strncpy((char *)tmpData, (const char *)bootCommandData, cnt);
-    tmpData[cnt] = '\0';
-    strcat((char *)tmpData, (const char *)bootArgsData);
-    
-    bootCommand = OSString::withCString((const char *)tmpData);
-    if (bootCommand != 0) {
-      _ofDict->setObject("boot-command", bootCommand);
-      bootCommand->release();
-    }
-    
-    IODelete(tmpData, UInt8, tmpDataLength + 1);
-  } else {
-    bootArgs = OSString::withCString((const char *)(bootCommandData + cnt));
-    if (bootArgs != 0) {
-      _ofDict->setObject("boot-args", bootArgs);
-      bootArgs->release();
-    }
-  }
-}
-
-
-// Private methods for Name Registry access.
-
-enum {
-  kMaxNVNameLength = 4,
-  kMaxNVDataLength = 8
-};
-
-#pragma options align=mac68k
-struct NVRAMProperty
-{
-  IONVRAMDescriptor   header;
-  UInt8               nameLength;
-  UInt8               name[ kMaxNVNameLength ];
-  UInt8               dataLength;
-  UInt8               data[ kMaxNVDataLength ];
-};
-#pragma options align=reset
-
-bool IODTNVRAM::searchNVRAMProperty(IONVRAMDescriptor *hdr, UInt32 *where)
-{
-  UInt32 offset;
-  SInt32 nvEnd;
-  
-  nvEnd = *((UInt16 *)_nrImage);
-  if(getPlatform()->getBootROMType()) {
-    // on NewWorld, offset to partition start
-    nvEnd -= 0x100;
-  } else {
-    // on old world, absolute
-    nvEnd -= _nrPartitionOffset;
-  }
-  if((nvEnd < 0) || (nvEnd >= kIODTNVRAMNameRegistrySize))
-    nvEnd = 2;
-  
-  offset = 2;
-  while ((offset + sizeof(NVRAMProperty)) <= (UInt32)nvEnd) {
-    if (bcmp(_nrImage + offset, hdr, sizeof(*hdr)) == 0) {
-      *where = offset;
-      return true;
-    }
-    offset += sizeof(NVRAMProperty);
-  }
-  
-  if ((nvEnd + sizeof(NVRAMProperty)) <= kIODTNVRAMNameRegistrySize)
-    *where = nvEnd;
-  else
-    *where = 0;
-  
-  return false;
-}
-
-IOReturn IODTNVRAM::readNVRAMPropertyType0(IORegistryEntry *entry,
-					   const OSSymbol **name,
-					   OSData **value)
-{
-  IONVRAMDescriptor hdr;
-  NVRAMProperty     *prop;
-  IOByteCount       length;
-  UInt32            offset;
-  IOReturn          err;
-  char              nameBuf[kMaxNVNameLength + 1];
-  
-  if (_nrImage == 0) return kIOReturnUnsupported;
-  if ((entry == 0) || (name == 0) || (value == 0)) return kIOReturnBadArgument;
-  
-  err = IODTMakeNVDescriptor(entry, &hdr);
-  if (err != kIOReturnSuccess) return err;
-  
-  if (searchNVRAMProperty(&hdr, &offset)) {
-    prop = (NVRAMProperty *)(_nrImage + offset);
-    
-    length = prop->nameLength;
-    if (length > kMaxNVNameLength) length = kMaxNVNameLength;
-    strncpy(nameBuf, (const char *)prop->name, length);
-    nameBuf[length] = 0;
-    *name = OSSymbol::withCString(nameBuf);
-    
-    length = prop->dataLength;
-    if (length > kMaxNVDataLength) length = kMaxNVDataLength;
-    *value = OSData::withBytes(prop->data, length);
-    
-    if ((*name != 0) && (*value != 0)) return kIOReturnSuccess;
-    else return kIOReturnNoMemory;
-  }
-  
-  return kIOReturnNoResources;
-}
-
-IOReturn IODTNVRAM::writeNVRAMPropertyType0(IORegistryEntry *entry,
-					    const OSSymbol *name,
-					    OSData *value)
-{
-  IONVRAMDescriptor hdr;
-  NVRAMProperty     *prop;
-  IOByteCount       nameLength;
-  IOByteCount       dataLength;
-  UInt32            offset;
-  IOReturn          err;
-  UInt16            nvLength;
-  bool              exists;
-  
-  if (_nrImage == 0) return kIOReturnUnsupported;
-  if ((entry == 0) || (name == 0) || (value == 0)) return kIOReturnBadArgument;
-  
-  nameLength = name->getLength();
-  dataLength = value->getLength();
-  if (nameLength > kMaxNVNameLength) return kIOReturnNoSpace;
-  if (dataLength > kMaxNVDataLength) return kIOReturnNoSpace;
-  
-  err = IODTMakeNVDescriptor(entry, &hdr);
-  if (err != kIOReturnSuccess) return err;
-  
-  exists = searchNVRAMProperty(&hdr, &offset);
-  if (offset == 0) return kIOReturnNoMemory;
-  
-  prop = (NVRAMProperty *)(_nrImage + offset);
-  if (!exists) bcopy(&hdr, &prop->header, sizeof(hdr));
-  
-  prop->nameLength = nameLength;
-  bcopy(name->getCStringNoCopy(), prop->name, nameLength);
-  prop->dataLength = dataLength;
-  bcopy(value->getBytesNoCopy(), prop->data, dataLength);
-  
-  if (!exists) {
-    nvLength = offset + sizeof(NVRAMProperty);
-    if (getPlatform()->getBootROMType())
-      nvLength += 0x100;
-    else
-      nvLength += _nrPartitionOffset;
-    *((UInt16 *)_nrImage) = nvLength;
-  }
-  
-  _nvramImageDirty = true;
-  
-  return err;
-}
-
-OSData *IODTNVRAM::unescapeBytesToData(UInt8 *bytes, UInt32 length)
-{
-  OSData *data = 0;
-  UInt32 totalLength = 0;
-  UInt32 cnt, cnt2;
-  UInt8  byte;
-  bool   ok;
-
-  // Calculate the actual length of the data.
-  ok = true;
-  totalLength = 0;
-  for (cnt = 0; cnt < length;) {
-    byte = bytes[cnt++];
-    if (byte == 0xFF) {
-      byte = bytes[cnt++];
-      if (byte == 0x00) {
-        ok = false;
-        break;
-      }
-      cnt2 = byte & 0x7F;
-    } else
-      cnt2 = 1;
-    totalLength += cnt2;
-  }
-
-  if (ok) {
-    // Create an empty OSData of the correct size.
-    data = OSData::withCapacity(totalLength);
-    if (data != 0) {
-      for (cnt = 0; cnt < length;) {
-        byte = bytes[cnt++];
-        if (byte == 0xFF) {
-          byte = bytes[cnt++];
-          cnt2 = byte & 0x7F;
-          byte = (byte & 0x80) ? 0xFF : 0x00;
-        } else
-          cnt2 = 1;
-        data->appendByte(byte, cnt2);
-      }
-    }
-  }
-
-  return data;
-}
-
-OSData * IODTNVRAM::escapeDataToData(OSData * value)
-{
-  OSData * result;
-  UInt8 *  start;
-  UInt8 *  end;
-  UInt8 *  where;
-  UInt8    byte;
-  bool	   ok = true;
-
-  where = (UInt8 *) value->getBytesNoCopy();
-  end = where + value->getLength();
-
-  result = OSData::withCapacity(end - where);
-  if (!result)
-    return result;
-
-  while (where < end) {
-    start = where;
-    byte = *where++;
-    if ((byte == 0x00) || (byte == 0xFF)) {
-      for (;
-            ((where - start) < 0x80) && (where < end) && (byte == *where);
-            where++)	{}
-      ok &= result->appendByte(0xff, 1);
-      byte = (byte & 0x80) | (where - start);
-    }
-    ok &= result->appendByte(byte, 1);
-  }
-  ok &= result->appendByte(0, 1);
-
-  if (!ok) {
-    result->release();
-    result = 0;
-  }
-
-  return result;
-}
-
-IOReturn IODTNVRAM::readNVRAMPropertyType1(IORegistryEntry *entry,
-					   const OSSymbol **name,
-					   OSData **value)
-{
-  IOReturn err = kIOReturnNoResources;
-  OSData   *data;
-  UInt8    *start;
-  UInt8    *end;
-  UInt8    *where;
-  UInt8    *nvPath = 0;
-  UInt8    *nvName = 0;
-  UInt8    byte;
-
-  if (_ofDict == 0) return err;
-  data = OSDynamicCast(OSData, _ofDict->getObject(_registryPropertiesKey));
-  if (data == 0) return err;
-  
-  start = (UInt8 *) data->getBytesNoCopy();
-  end = start + data->getLength();
-
-  where = start;
-  while (where < end) {
-    byte = *(where++);
-    if (byte)
-      continue;
-    
-    if (nvPath == 0)
-      nvPath = start;
-    else if (nvName == 0)
-      nvName = start;
-    else {
-      IORegistryEntry * compareEntry = IORegistryEntry::fromPath((const char *) nvPath, gIODTPlane);
-      if (entry == compareEntry) {
-        if (compareEntry)
-          compareEntry->release();
-	*name = OSSymbol::withCString((const char *) nvName);
-	*value = unescapeBytesToData(start, where - start - 1);
-	if ((*name != 0) && (*value != 0))
-	  err = kIOReturnSuccess;
-	else
-	  err = kIOReturnNoMemory;
-	break;
-      }
-      if (compareEntry)
-        compareEntry->release();
-      nvPath = nvName = 0;
-    }
-    start = where;
-  }
-
-  return err;
-}
-
-IOReturn IODTNVRAM::writeNVRAMPropertyType1(IORegistryEntry *entry,
-					    const OSSymbol *propName,
-					    OSData *value)
-{
-  OSData   *oldData;
-  OSData   *data = 0;
-  UInt8    *start;
-  UInt8    *propStart;
-  UInt8    *end;
-  UInt8    *where;
-  UInt8    *nvPath = 0;
-  UInt8    *nvName = 0;
-  const char * comp;
-  const char * name;
-  UInt8     byte;
-  bool      ok = true;
-
-  if (_ofDict == 0) return kIOReturnNoResources;
-
-  // copy over existing properties for other entries
-
-  oldData = OSDynamicCast(OSData, _ofDict->getObject(_registryPropertiesKey));
-  if (oldData) {
-    start = (UInt8 *) oldData->getBytesNoCopy();
-    end = start + oldData->getLength();
-    
-    propStart = start;
-    where = start;
-    while (where < end) {
-      byte = *(where++);
-      if (byte)
-        continue;
-      if (nvPath == 0)
-        nvPath = start;
-      else if (nvName == 0)
-        nvName = start;
-      else {
-        IORegistryEntry * compareEntry = IORegistryEntry::fromPath((const char *) nvPath, gIODTPlane);
-        if (entry == compareEntry) {
-          if (compareEntry)
-             compareEntry->release();
-           // delete old property (nvPath -> where)
-           data = OSData::withBytes(propStart, nvPath - propStart);
-           if (data)
-             ok &= data->appendBytes(where, end - where);
-	   break;
-        }
-        if (compareEntry)
-          compareEntry->release();
-        nvPath = nvName = 0;
-      }
-        
-      start = where;
-    }
-  }
-
-  // make the new property
-
-  if (!data) {
-    if (oldData)
-      data = OSData::withData(oldData);
-    else
-      data = OSData::withCapacity(16);
-    if (!data)
-      return kIOReturnNoMemory;
-  }
-
-  // get entries in path
-  OSArray *array = OSArray::withCapacity(5);
-  if (!array) {
-    data->release();
-    return kIOReturnNoMemory;
-  }
-  do
-    array->setObject(entry);
-  while ((entry = entry->getParentEntry(gIODTPlane)));
-
-  // append path
-  for (int i = array->getCount() - 3;
-        (entry = (IORegistryEntry *) array->getObject(i));
-        i--) {
-
-    name = entry->getName(gIODTPlane);
-    comp = entry->getLocation(gIODTPlane);
-    if( comp && (0 == strcmp("pci", name))
-     && (0 == strcmp("80000000", comp))) {
-      // yosemite hack
-      comp = "/pci@80000000";
-    } else {
-      if (comp)
-        ok &= data->appendBytes("/@", 2);
-      else {
-        if (!name)
-          continue;
-        ok &= data->appendByte('/', 1);
-        comp = name;
-      }
-    }
-    ok &= data->appendBytes(comp, strlen(comp));
-  }
-  ok &= data->appendByte(0, 1);
-  array->release();
-
-  // append prop name
-  ok &= data->appendBytes(propName->getCStringNoCopy(), propName->getLength() + 1);
-  
-  // append escaped data
-  oldData = escapeDataToData(value);
-  ok &= (oldData != 0);
-  if (ok)
-    ok &= data->appendBytes(oldData);
-
-  if (ok) {
-    ok = _ofDict->setObject(_registryPropertiesKey, data);
-    if (ok)
-      _ofImageDirty = true;
-  }
-  data->release();
-
-  return ok ? kIOReturnSuccess : kIOReturnNoMemory;
-}
+
+	case kOFVariableTypeString:
+		offset += strlcpy((char *)buffer, tmpString->getCStringNoCopy(), remaining);
+		break;
+
+	case kOFVariableTypeData:
+		if (buffer) {
+			bcopy(tmpData->getBytesNoCopy(), buffer, propDataLength);
+		}
+		tmpData.reset();
+		offset += propDataLength;
+		break;
+
+	default:
+		break;
+	}
+
+	*length = offset + 1;
+
+	return true;
+}
+
+OSSharedPtr<OSData>
+IODTNVRAM::unescapeBytesToData(const UInt8 *bytes, UInt32 length)
+{
+	OSSharedPtr<OSData> data;
+	UInt32              totalLength = 0;
+	UInt32              offset, offset2;
+	UInt8               byte;
+	bool                ok;
+
+	// Calculate the actual length of the data.
+	ok = true;
+	totalLength = 0;
+	for (offset = 0; offset < length;) {
+		byte = bytes[offset++];
+		if (byte == 0xFF) {
+			byte = bytes[offset++];
+			if (byte == 0x00) {
+				ok = false;
+				break;
+			}
+			offset2 = byte & 0x7F;
+		} else {
+			offset2 = 1;
+		}
+		totalLength += offset2;
+	}
+
+	if (ok) {
+		// Create an empty OSData of the correct size.
+		data = OSData::withCapacity(totalLength);
+		if (data != nullptr) {
+			for (offset = 0; offset < length;) {
+				byte = bytes[offset++];
+				if (byte == 0xFF) {
+					byte = bytes[offset++];
+					offset2 = byte & 0x7F;
+					byte = (byte & 0x80) ? 0xFF : 0x00;
+				} else {
+					offset2 = 1;
+				}
+				data->appendByte(byte, offset2);
+			}
+		}
+	}
+
+	return data;
+}
+
+OSSharedPtr<OSData>
+IODTNVRAM::escapeDataToData(OSData * value)
+{
+	OSSharedPtr<OSData> result;
+	const UInt8         *startPtr;
+	const UInt8         *endPtr;
+	const UInt8         *wherePtr;
+	UInt8               byte;
+	bool                ok = true;
+
+	wherePtr = (const UInt8 *) value->getBytesNoCopy();
+	endPtr = wherePtr + value->getLength();
+
+	result = OSData::withCapacity((unsigned int) (endPtr - wherePtr));
+	if (!result) {
+		return result;
+	}
+
+	while (wherePtr < endPtr) {
+		startPtr = wherePtr;
+		byte = *wherePtr++;
+		if ((byte == 0x00) || (byte == 0xFF)) {
+			for (;
+			    ((wherePtr - startPtr) < 0x7F) && (wherePtr < endPtr) && (byte == *wherePtr);
+			    wherePtr++) {
+			}
+			ok &= result->appendByte(0xff, 1);
+			byte = (byte & 0x80) | ((UInt8)(wherePtr - startPtr));
+		}
+		ok &= result->appendByte(byte, 1);
+	}
+	ok &= result->appendByte(0, 1);
+
+	if (!ok) {
+		result.reset();
+	}
+
+	return result;
+}
+
+static bool
+IsApplePropertyName(const char * propName)
+{
+	char c;
+	while ((c = *propName++)) {
+		if ((c >= 'A') && (c <= 'Z')) {
+			break;
+		}
+	}
+
+	return c == 0;
+}
+
+IOReturn
+IODTNVRAM::readNVRAMPropertyType1(IORegistryEntry *entry,
+    const OSSymbol **name,
+    OSData **value)
+{
+	IOReturn    err = kIOReturnNoResources;
+	OSData      *data;
+	const UInt8 *startPtr;
+	const UInt8 *endPtr;
+	const UInt8 *wherePtr;
+	const UInt8 *nvPath = nullptr;
+	const char  *nvName = nullptr;
+	const char  *resultName = nullptr;
+	const UInt8 *resultValue = nullptr;
+	UInt32       resultValueLen = 0;
+	UInt8       byte;
+
+	NVRAMREADLOCK();
+	data = OSDynamicCast(OSData, _commonDict->getObject(_registryPropertiesKey.get()));
+	NVRAMUNLOCK();
+
+	if (data == nullptr) {
+		return err;
+	}
+
+	startPtr = (const UInt8 *) data->getBytesNoCopy();
+	endPtr = startPtr + data->getLength();
+
+	wherePtr = startPtr;
+	while (wherePtr < endPtr) {
+		byte = *(wherePtr++);
+		if (byte) {
+			continue;
+		}
+
+		if (nvPath == nullptr) {
+			nvPath = startPtr;
+		} else if (nvName == nullptr) {
+			nvName = (const char *) startPtr;
+		} else {
+			OSSharedPtr<IORegistryEntry> compareEntry = IORegistryEntry::fromPath((const char *) nvPath, gIODTPlane);
+			if (entry == compareEntry) {
+				bool appleProp = IsApplePropertyName(nvName);
+				if (!appleProp || !resultName) {
+					resultName     = nvName;
+					resultValue    = startPtr;
+					resultValueLen = (UInt32) (wherePtr - startPtr - 1);  // OSData getLength() is 32b
+				}
+				if (!appleProp) {
+					break;
+				}
+			}
+			nvPath = nullptr;
+			nvName = nullptr;
+		}
+		startPtr = wherePtr;
+	}
+	if (resultName) {
+		*name = OSSymbol::withCString(resultName).detach();
+		*value = unescapeBytesToData(resultValue, resultValueLen).detach();
+		if ((*name != nullptr) && (*value != nullptr)) {
+			err = kIOReturnSuccess;
+		} else {
+			err = kIOReturnNoMemory;
+		}
+	}
+	return err;
+}
+
+IOReturn
+IODTNVRAM::writeNVRAMPropertyType1(IORegistryEntry *entry,
+    const OSSymbol *propName,
+    OSData *value)
+{
+	OSSharedPtr<OSData> data, oldData;
+	const UInt8         *startPtr;
+	const UInt8         *propStart;
+	const UInt8         *endPtr;
+	const UInt8         *wherePtr;
+	const UInt8         *nvPath = nullptr;
+	const char          *nvName = nullptr;
+	const char          *comp;
+	const char          *name;
+	UInt8               byte;
+	bool                ok = true;
+	bool                settingAppleProp;
+
+	settingAppleProp = IsApplePropertyName(propName->getCStringNoCopy());
+
+	// copy over existing properties for other entries
+
+	NVRAMWRITELOCK();
+
+	oldData.reset(OSDynamicCast(OSData, _commonDict->getObject(_registryPropertiesKey.get())), OSRetain);
+	if (oldData) {
+		startPtr = (const UInt8 *) oldData->getBytesNoCopy();
+		endPtr = startPtr + oldData->getLength();
+
+		propStart = startPtr;
+		wherePtr = startPtr;
+		while (wherePtr < endPtr) {
+			byte = *(wherePtr++);
+			if (byte) {
+				continue;
+			}
+			if (nvPath == nullptr) {
+				nvPath = startPtr;
+			} else if (nvName == nullptr) {
+				nvName = (const char *) startPtr;
+			} else {
+				OSSharedPtr<IORegistryEntry> compareEntry = IORegistryEntry::fromPath((const char *) nvPath, gIODTPlane);
+
+				if (entry == compareEntry) {
+					if ((settingAppleProp && propName->isEqualTo(nvName))
+					    || (!settingAppleProp && !IsApplePropertyName(nvName))) {
+						// delete old property (nvPath -> wherePtr) source OSData len is 32b
+						data = OSData::withBytes(propStart, (UInt32)(nvPath - propStart));
+						if (data) {
+							ok &= data->appendBytes(wherePtr, (UInt32)(endPtr - wherePtr));
+						}
+						break;
+					}
+				}
+				nvPath = nullptr;
+				nvName = nullptr;
+			}
+
+			startPtr = wherePtr;
+		}
+	}
+
+	// make the new property
+
+	if (!data) {
+		if (oldData) {
+			data = OSData::withData(oldData.get());
+		} else {
+			data = OSData::withCapacity(16);
+		}
+		if (!data) {
+			ok = false;
+		}
+	}
+
+	if (ok && value && value->getLength()) {
+		do {
+			// get entries in path
+			OSSharedPtr<OSArray> array = OSArray::withCapacity(5);
+			if (!array) {
+				ok = false;
+				break;
+			}
+			do{
+				array->setObject(entry);
+			} while ((entry = entry->getParentEntry(gIODTPlane)));
+
+			// append path
+			for (int i = array->getCount() - 3;
+			    (entry = (IORegistryEntry *) array->getObject(i));
+			    i--) {
+				name = entry->getName(gIODTPlane);
+				comp = entry->getLocation(gIODTPlane);
+				if (comp) {
+					ok &= data->appendBytes("/@", 2);
+				} else {
+					if (!name) {
+						continue;
+					}
+					ok &= data->appendByte('/', 1);
+					comp = name;
+				}
+				ok &= data->appendBytes(comp, (unsigned int) strnlen(comp, UINT16_MAX));
+			}
+			ok &= data->appendByte(0, 1);
+			// append prop name
+			ok &= data->appendBytes(propName->getCStringNoCopy(), propName->getLength() + 1);
+
+			// append escaped data
+			OSSharedPtr<OSData> escapedData = escapeDataToData(value);
+			ok &= (escapedData != nullptr);
+			if (ok) {
+				ok &= data->appendBytes(escapedData.get());
+			}
+		} while (false);
+	}
+
+	if (ok) {
+		ok = _commonDict->setObject(_registryPropertiesKey.get(), data.get());
+	}
+
+	NVRAMUNLOCK();
+
+	if (ok) {
+		if (serializeVariables() != kIOReturnSuccess) {
+			NVRAMWRITELOCK();
+			if (oldData) {
+				_commonDict->setObject(_registryPropertiesKey.get(), oldData.get());
+			} else {
+				_commonDict->removeObject(_registryPropertiesKey.get());
+			}
+			NVRAMUNLOCK();
+
+			(void) serializeVariables();
+			ok = false;
+		}
+	}
+
+	oldData.reset();
+
+	return ok ? kIOReturnSuccess : kIOReturnNoSpace;
+}
+
+bool
+IODTNVRAM::safeToSync(void)
+{
+	AbsoluteTime delta;
+	UInt64       delta_ns;
+	SInt32       delta_secs;
+
+	// delta interval went by
+	clock_get_uptime(&delta);
+
+	// Figure it in seconds.
+	absolutetime_to_nanoseconds(delta, &delta_ns);
+	delta_secs = (SInt32)(delta_ns / NSEC_PER_SEC);
+
+	if ((delta_secs > (_lastDeviceSync + MIN_SYNC_NOW_INTERVAL)) || _freshInterval) {
+		_lastDeviceSync = delta_secs;
+		_freshInterval = FALSE;
+		return TRUE;
+	}
+
+	return FALSE;
+}