[mirror_edk2.git] / MdeModulePkg / Universal / DebugSupportDxe / Ia32 / PlDebugSupport.c

/** @file\r
  Generic debug support functions for IA32/x64.\r
\r
Copyright (c) 2006 - 2008, Intel Corporation\r
All rights reserved. This program and the accompanying materials\r
are licensed and made available under the terms and conditions of the BSD License\r
which accompanies this distribution.  The full text of the license may be found at\r
http://opensource.org/licenses/bsd-license.php\r
\r
THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r
WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
\r
**/\r
\r
#include "DebugSupport.h"\r
\r
//\r
// This the global main table to keep track of the interrupts\r
//\r
IDT_ENTRY                 *IdtEntryTable  = NULL;\r
IA32_IDT_GATE_DESCRIPTOR  NullDesc        = {0};\r
\r
/**\r
  Read IDT Gate Descriptor from IDT Table.\r
\r
  @param  Vector            Specifies vector number.\r
  @param  IdtGateDescriptor Pointer to IDT Gate Descriptor read from IDT Table.\r
\r
**/\r
VOID\r
ReadIdtGateDescriptor (\r
  IN  EFI_EXCEPTION_TYPE        Vector,\r
  OUT IA32_IDT_GATE_DESCRIPTOR  *IdtGateDescriptor\r
  )\r
{\r
 IA32_DESCRIPTOR            IdtrValue;\r
 IA32_IDT_GATE_DESCRIPTOR   *IdtTable;\r
\r
 AsmReadIdtr (&IdtrValue);\r
 IdtTable = (IA32_IDT_GATE_DESCRIPTOR *) IdtrValue.Base;\r
\r
 CopyMem ((VOID *) IdtGateDescriptor, (VOID *) &(IdtTable)[Vector], sizeof (IA32_IDT_GATE_DESCRIPTOR));\r
}\r
\r
/**\r
  Write IDT Gate Descriptor into IDT Table.\r
\r
  @param  Vector            Specifies vector number.\r
  @param  IdtGateDescriptor Pointer to IDT Gate Descriptor written into IDT Table.\r
\r
**/\r
VOID\r
WriteIdtGateDescriptor (\r
  EFI_EXCEPTION_TYPE        Vector,\r
  IA32_IDT_GATE_DESCRIPTOR  *IdtGateDescriptor\r
  )\r
{\r
 IA32_DESCRIPTOR            IdtrValue;\r
 IA32_IDT_GATE_DESCRIPTOR   *IdtTable;\r
\r
 AsmReadIdtr (&IdtrValue);\r
 IdtTable = (IA32_IDT_GATE_DESCRIPTOR *) IdtrValue.Base;\r
\r
 CopyMem ((VOID *) &(IdtTable)[Vector], (VOID *) IdtGateDescriptor, sizeof (IA32_IDT_GATE_DESCRIPTOR));\r
}\r
\r
/**\r
  Creates a nes entry stub.  Then saves the current IDT entry and replaces it\r
  with an interrupt gate for the new entry point.  The IdtEntryTable is updated\r
  with the new registered function.\r
\r
  This code executes in boot services context.  The stub entry executes in interrupt\r
  context.\r
\r
  @param  ExceptionType      Specifies which vector to hook.\r
  @param  NewCallback        A pointer to the new function to be registered.\r
\r
**/\r
VOID\r
HookEntry (\r
  IN EFI_EXCEPTION_TYPE            ExceptionType,\r
  IN VOID                         (*NewCallback) ()\r
  )\r
{\r
  BOOLEAN     OldIntFlagState;\r
\r
  CreateEntryStub (ExceptionType, (VOID **) &IdtEntryTable[ExceptionType].StubEntry);\r
                          \r
  //\r
  // Disables CPU interrupts and returns the previous interrupt state\r
  //\r
  OldIntFlagState = SaveAndDisableInterrupts ();\r
\r
  ReadIdtGateDescriptor (ExceptionType, &(IdtEntryTable[ExceptionType].OrigDesc));\r
  IdtEntryTable[ExceptionType].OrigVector = (DEBUG_PROC) GetInterruptHandleFromIdt (&(IdtEntryTable[ExceptionType].OrigDesc));\r
\r
  Vect2Desc (&IdtEntryTable[ExceptionType].NewDesc, IdtEntryTable[ExceptionType].StubEntry);\r
  IdtEntryTable[ExceptionType].RegisteredCallback = NewCallback;\r
  WriteIdtGateDescriptor (ExceptionType, &(IdtEntryTable[ExceptionType].NewDesc));\r
\r
  //\r
  // restore interrupt state\r
  //\r
  SetInterruptState (OldIntFlagState);\r
\r
  return ;\r
}\r
\r
/**\r
  Undoes HookEntry. This code executes in boot services context.\r
\r
  @param  ExceptionType   Specifies which entry to unhook\r
\r
**/\r
VOID\r
UnhookEntry (\r
  IN EFI_EXCEPTION_TYPE           ExceptionType\r
  )\r
{\r
  BOOLEAN     OldIntFlagState;\r
\r
  //\r
  // Disables CPU interrupts and returns the previous interrupt state\r
  //\r
  OldIntFlagState = SaveAndDisableInterrupts ();\r
\r
  //\r
  // restore the default IDT Date Descriptor\r
  //\r
  WriteIdtGateDescriptor (ExceptionType, &(IdtEntryTable[ExceptionType].OrigDesc));\r
\r
  //\r
  // restore interrupt state\r
  //\r
  SetInterruptState (OldIntFlagState);\r
\r
  return ;\r
}\r
\r
/**\r
  Returns the maximum value that may be used for the ProcessorIndex parameter in\r
  RegisterPeriodicCallback() and RegisterExceptionCallback().                   \r
    \r
  Hard coded to support only 1 processor for now.\r
\r
  @param  This                  A pointer to the EFI_DEBUG_SUPPORT_PROTOCOL instance.\r
  @param  MaxProcessorIndex     Pointer to a caller-allocated UINTN in which the maximum supported\r
                                processor index is returned. Always 0 returned.                                     \r
                                \r
  @retval EFI_SUCCESS           Always returned with **MaxProcessorIndex set to 0.\r
\r
**/\r
EFI_STATUS\r
EFIAPI\r
GetMaximumProcessorIndex (\r
  IN EFI_DEBUG_SUPPORT_PROTOCOL       *This,\r
  OUT UINTN                           *MaxProcessorIndex\r
  )\r
{\r
  *MaxProcessorIndex = 0;\r
  return EFI_SUCCESS;\r
}\r
\r
/**\r
  Registers a function to be called back periodically in interrupt context.\r
    \r
  @param  This                  A pointer to the EFI_DEBUG_SUPPORT_PROTOCOL instance.\r
  @param  ProcessorIndex        Specifies which processor the callback function applies to.\r
  @param  PeriodicCallback      A pointer to a function of type PERIODIC_CALLBACK that is the main\r
                                periodic entry point of the debug agent.\r
                                \r
  @retval EFI_SUCCESS           The function completed successfully.  \r
  @retval EFI_ALREADY_STARTED   Non-NULL PeriodicCallback parameter when a callback\r
                                function was previously registered.                \r
  @retval EFI_OUT_OF_RESOURCES  System has insufficient memory resources to register new callback                               \r
                                function. \r
**/\r
EFI_STATUS\r
EFIAPI\r
RegisterPeriodicCallback (\r
  IN EFI_DEBUG_SUPPORT_PROTOCOL *This,\r
  IN UINTN                      ProcessorIndex,\r
  IN EFI_PERIODIC_CALLBACK      PeriodicCallback\r
  )\r
{\r
  return ManageIdtEntryTable (PeriodicCallback, SYSTEM_TIMER_VECTOR);\r
}\r
\r
/**\r
  Registers a function to be called when a given processor exception occurs.\r
\r
  This code executes in boot services context.\r
    \r
  @param  This                  A pointer to the EFI_DEBUG_SUPPORT_PROTOCOL instance.\r
  @param  ProcessorIndex        Specifies which processor the callback function applies to.\r
  @param  ExceptionCallback     A pointer to a function of type EXCEPTION_CALLBACK that is called\r
                                when the processor exception specified by ExceptionType occurs.  \r
  @param  ExceptionType         Specifies which processor exception to hook.                       \r
                                \r
  @retval EFI_SUCCESS           The function completed successfully.  \r
  @retval EFI_ALREADY_STARTED   Non-NULL PeriodicCallback parameter when a callback\r
                                function was previously registered.                \r
  @retval EFI_OUT_OF_RESOURCES  System has insufficient memory resources to register new callback                               \r
                                function.\r
**/\r
EFI_STATUS\r
EFIAPI\r
RegisterExceptionCallback (\r
  IN EFI_DEBUG_SUPPORT_PROTOCOL *This,\r
  IN UINTN                      ProcessorIndex,\r
  IN EFI_EXCEPTION_CALLBACK     ExceptionCallback,\r
  IN EFI_EXCEPTION_TYPE         ExceptionType\r
  )\r
{\r
  return ManageIdtEntryTable (ExceptionCallback, ExceptionType);\r
}\r
\r
/**\r
  Invalidates processor instruction cache for a memory range. Subsequent execution in this range\r
  causes a fresh memory fetch to retrieve code to be executed.                                  \r
    \r
  @param  This                  A pointer to the EFI_DEBUG_SUPPORT_PROTOCOL instance.\r
  @param  ProcessorIndex        Specifies which processor's instruction cache is to be invalidated.\r
  @param  Start                 Specifies the physical base of the memory range to be invalidated.                                \r
  @param  Length                Specifies the minimum number of bytes in the processor's instruction\r
                                cache to invalidate.                                                 \r
                                \r
  @retval EFI_SUCCESS           Always returned.\r
\r
**/\r
EFI_STATUS\r
EFIAPI\r
InvalidateInstructionCache (\r
  IN EFI_DEBUG_SUPPORT_PROTOCOL       *This,\r
  IN UINTN                            ProcessorIndex,\r
  IN VOID                             *Start,\r
  IN UINT64                           Length\r
  )\r
{\r
  AsmWbinvd ();\r
  return EFI_SUCCESS;\r
}\r
\r
/**\r
  Common piece of code that invokes the registered handlers.\r
\r
  This code executes in exception context so no efi calls are allowed.\r
\r
  @param  ExceptionType     Exception type\r
  @param  ContextRecord     System context\r
\r
**/\r
VOID\r
InterruptDistrubutionHub (\r
  EFI_EXCEPTION_TYPE      ExceptionType,\r
  EFI_SYSTEM_CONTEXT_IA32 *ContextRecord\r
  )\r
{\r
  if (IdtEntryTable[ExceptionType].RegisteredCallback != NULL) {\r
    if (ExceptionType != SYSTEM_TIMER_VECTOR) {\r
      IdtEntryTable[ExceptionType].RegisteredCallback (ExceptionType, ContextRecord);\r
    } else {\r
      OrigVector = IdtEntryTable[ExceptionType].OrigVector;\r
      IdtEntryTable[ExceptionType].RegisteredCallback (ContextRecord);\r
    }\r
  }\r
}\r
\r
/**\r
  This is the callback that is written to the Loaded Image protocol instance\r
  on the image handle. It uninstalls all registered handlers and frees all entry\r
  stub memory.\r
\r
  @param  ImageHandle    The firmware allocated handle for the EFI image.\r
\r
  @retval EFI_SUCCESS    Always.\r
\r
**/\r
EFI_STATUS\r
EFIAPI\r
PlUnloadDebugSupportDriver (\r
  IN EFI_HANDLE ImageHandle\r
  )\r
{\r
  EFI_EXCEPTION_TYPE  ExceptionType;\r
\r
  for (ExceptionType = 0; ExceptionType < NUM_IDT_ENTRIES; ExceptionType++) {\r
    ManageIdtEntryTable (NULL, ExceptionType);\r
    //\r
    // Free space for each Interrupt Stub precedure.\r
    //\r
    if (IdtEntryTable[ExceptionType].StubEntry != NULL) {\r
      FreePool ((VOID *)(UINTN)IdtEntryTable[ExceptionType].StubEntry);\r
    }\r
  }\r
\r
  FreePool (IdtEntryTable);\r
\r
  return EFI_SUCCESS;\r
}\r
\r
/**\r
  Initializes driver's handler registration database. \r
  \r
  This code executes in boot services context.\r
  Must be public because it's referenced from DebugSupport.c\r
\r
  @retval  EFI_UNSUPPORTED      If IA32/x64 processor does not support FXSTOR/FXRSTOR instructions,\r
                                the context save will fail, so these processors are not supported.\r
  @retval  EFI_OUT_OF_RESOURCES Fails to allocate memory.\r
  @retval  EFI_SUCCESS          Initializes successfully.\r
\r
**/\r
EFI_STATUS\r
PlInitializeDebugSupportDriver (\r
  VOID\r
  )\r
{\r
  EFI_EXCEPTION_TYPE  ExceptionType;\r
\r
  //\r
  // Check whether FxStor instructions are supported.\r
  //\r
  if (!FxStorSupport ()) {\r
    return EFI_UNSUPPORTED;\r
  }\r
\r
  IdtEntryTable = AllocateZeroPool (sizeof (IDT_ENTRY) * NUM_IDT_ENTRIES);\r
  if (IdtEntryTable == NULL) {\r
    return EFI_OUT_OF_RESOURCES;\r
  }\r
\r
  for (ExceptionType = 0; ExceptionType < NUM_IDT_ENTRIES; ExceptionType ++) {\r
    IdtEntryTable[ExceptionType].StubEntry = (DEBUG_PROC) (UINTN) AllocatePool (StubSize);\r
    if (IdtEntryTable[ExceptionType].StubEntry == NULL) {\r
      goto ErrorCleanup;\r
    }\r
    \r
    //\r
    // Copy Interrupt stub code.\r
    //\r
    CopyMem ((VOID *)(UINTN)IdtEntryTable[ExceptionType].StubEntry, InterruptEntryStub, StubSize);\r
  }\r
  return EFI_SUCCESS;\r
\r
ErrorCleanup:\r
\r
  for (ExceptionType = 0; ExceptionType < NUM_IDT_ENTRIES; ExceptionType++) {\r
    if (IdtEntryTable[ExceptionType].StubEntry != NULL) {\r
      FreePool ((VOID *)(UINTN)IdtEntryTable[ExceptionType].StubEntry);\r
    }\r
  }\r
  FreePool (IdtEntryTable);\r
\r
  return EFI_OUT_OF_RESOURCES;\r
}\r
Commit	Line	Data
	1	/** @file\r
	2	Generic debug support functions for IA32/x64.\r
	3	\r
	4	Copyright (c) 2006 - 2008, Intel Corporation\r
	5	All rights reserved. This program and the accompanying materials\r
	6	are licensed and made available under the terms and conditions of the BSD License\r
	7	which accompanies this distribution. The full text of the license may be found at\r
	8	http://opensource.org/licenses/bsd-license.php\r
	9	\r
	10	THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r
	11	WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
	12	\r
	13	**/\r
	14	\r
	15	#include "DebugSupport.h"\r
	16	\r
	17	//\r
	18	// This the global main table to keep track of the interrupts\r
	19	//\r
	20	IDT_ENTRY *IdtEntryTable = NULL;\r
	21	IA32_IDT_GATE_DESCRIPTOR NullDesc = {0};\r
	22	\r
	23	/**\r
	24	Read IDT Gate Descriptor from IDT Table.\r
	25	\r
	26	@param Vector Specifies vector number.\r
	27	@param IdtGateDescriptor Pointer to IDT Gate Descriptor read from IDT Table.\r
	28	\r
	29	**/\r
	30	VOID\r
	31	ReadIdtGateDescriptor (\r
	32	IN EFI_EXCEPTION_TYPE Vector,\r
	33	OUT IA32_IDT_GATE_DESCRIPTOR *IdtGateDescriptor\r
	34	)\r
	35	{\r
	36	IA32_DESCRIPTOR IdtrValue;\r
	37	IA32_IDT_GATE_DESCRIPTOR *IdtTable;\r
	38	\r
	39	AsmReadIdtr (&IdtrValue);\r
	40	IdtTable = (IA32_IDT_GATE_DESCRIPTOR *) IdtrValue.Base;\r
	41	\r
	42	CopyMem ((VOID ) IdtGateDescriptor, (VOID ) &(IdtTable)[Vector], sizeof (IA32_IDT_GATE_DESCRIPTOR));\r
	43	}\r
	44	\r
	45	/**\r
	46	Write IDT Gate Descriptor into IDT Table.\r
	47	\r
	48	@param Vector Specifies vector number.\r
	49	@param IdtGateDescriptor Pointer to IDT Gate Descriptor written into IDT Table.\r
	50	\r
	51	**/\r
	52	VOID\r
	53	WriteIdtGateDescriptor (\r
	54	EFI_EXCEPTION_TYPE Vector,\r
	55	IA32_IDT_GATE_DESCRIPTOR *IdtGateDescriptor\r
	56	)\r
	57	{\r
	58	IA32_DESCRIPTOR IdtrValue;\r
	59	IA32_IDT_GATE_DESCRIPTOR *IdtTable;\r
	60	\r
	61	AsmReadIdtr (&IdtrValue);\r
	62	IdtTable = (IA32_IDT_GATE_DESCRIPTOR *) IdtrValue.Base;\r
	63	\r
	64	CopyMem ((VOID ) &(IdtTable)[Vector], (VOID ) IdtGateDescriptor, sizeof (IA32_IDT_GATE_DESCRIPTOR));\r
	65	}\r
	66	\r
	67	/**\r
	68	Creates a nes entry stub. Then saves the current IDT entry and replaces it\r
	69	with an interrupt gate for the new entry point. The IdtEntryTable is updated\r
	70	with the new registered function.\r
	71	\r
	72	This code executes in boot services context. The stub entry executes in interrupt\r
	73	context.\r
	74	\r
	75	@param ExceptionType Specifies which vector to hook.\r
	76	@param NewCallback A pointer to the new function to be registered.\r
	77	\r
	78	**/\r
	79	VOID\r
	80	HookEntry (\r
	81	IN EFI_EXCEPTION_TYPE ExceptionType,\r
	82	IN VOID (*NewCallback) ()\r
	83	)\r
	84	{\r
	85	BOOLEAN OldIntFlagState;\r
	86	\r
	87	CreateEntryStub (ExceptionType, (VOID **) &IdtEntryTable[ExceptionType].StubEntry);\r
	88	\r
	89	//\r
	90	// Disables CPU interrupts and returns the previous interrupt state\r
	91	//\r
	92	OldIntFlagState = SaveAndDisableInterrupts ();\r
	93	\r
	94	ReadIdtGateDescriptor (ExceptionType, &(IdtEntryTable[ExceptionType].OrigDesc));\r
	95	IdtEntryTable[ExceptionType].OrigVector = (DEBUG_PROC) GetInterruptHandleFromIdt (&(IdtEntryTable[ExceptionType].OrigDesc));\r
	96	\r
	97	Vect2Desc (&IdtEntryTable[ExceptionType].NewDesc, IdtEntryTable[ExceptionType].StubEntry);\r
	98	IdtEntryTable[ExceptionType].RegisteredCallback = NewCallback;\r
	99	WriteIdtGateDescriptor (ExceptionType, &(IdtEntryTable[ExceptionType].NewDesc));\r
	100	\r
	101	//\r
	102	// restore interrupt state\r
	103	//\r
	104	SetInterruptState (OldIntFlagState);\r
	105	\r
	106	return ;\r
	107	}\r
	108	\r
	109	/**\r
	110	Undoes HookEntry. This code executes in boot services context.\r
	111	\r
	112	@param ExceptionType Specifies which entry to unhook\r
	113	\r
	114	**/\r
	115	VOID\r
	116	UnhookEntry (\r
	117	IN EFI_EXCEPTION_TYPE ExceptionType\r
	118	)\r
	119	{\r
	120	BOOLEAN OldIntFlagState;\r
	121	\r
	122	//\r
	123	// Disables CPU interrupts and returns the previous interrupt state\r
	124	//\r
	125	OldIntFlagState = SaveAndDisableInterrupts ();\r
	126	\r
	127	//\r
	128	// restore the default IDT Date Descriptor\r
	129	//\r
	130	WriteIdtGateDescriptor (ExceptionType, &(IdtEntryTable[ExceptionType].OrigDesc));\r
	131	\r
	132	//\r
	133	// restore interrupt state\r
	134	//\r
	135	SetInterruptState (OldIntFlagState);\r
	136	\r
	137	return ;\r
	138	}\r
	139	\r
	140	/**\r
	141	Returns the maximum value that may be used for the ProcessorIndex parameter in\r
	142	RegisterPeriodicCallback() and RegisterExceptionCallback(). \r
	143	\r
	144	Hard coded to support only 1 processor for now.\r
	145	\r
	146	@param This A pointer to the EFI_DEBUG_SUPPORT_PROTOCOL instance.\r
	147	@param MaxProcessorIndex Pointer to a caller-allocated UINTN in which the maximum supported\r
	148	processor index is returned. Always 0 returned. \r
	149	\r
	150	@retval EFI_SUCCESS Always returned with **MaxProcessorIndex set to 0.\r
	151	\r
	152	**/\r
	153	EFI_STATUS\r
	154	EFIAPI\r
	155	GetMaximumProcessorIndex (\r
	156	IN EFI_DEBUG_SUPPORT_PROTOCOL *This,\r
	157	OUT UINTN *MaxProcessorIndex\r
	158	)\r
	159	{\r
	160	*MaxProcessorIndex = 0;\r
	161	return EFI_SUCCESS;\r
	162	}\r
	163	\r
	164	/**\r
	165	Registers a function to be called back periodically in interrupt context.\r
	166	\r
	167	@param This A pointer to the EFI_DEBUG_SUPPORT_PROTOCOL instance.\r
	168	@param ProcessorIndex Specifies which processor the callback function applies to.\r
	169	@param PeriodicCallback A pointer to a function of type PERIODIC_CALLBACK that is the main\r
	170	periodic entry point of the debug agent.\r
	171	\r
	172	@retval EFI_SUCCESS The function completed successfully. \r
	173	@retval EFI_ALREADY_STARTED Non-NULL PeriodicCallback parameter when a callback\r
	174	function was previously registered. \r
	175	@retval EFI_OUT_OF_RESOURCES System has insufficient memory resources to register new callback \r
	176	function. \r
	177	**/\r
	178	EFI_STATUS\r
	179	EFIAPI\r
	180	RegisterPeriodicCallback (\r
	181	IN EFI_DEBUG_SUPPORT_PROTOCOL *This,\r
	182	IN UINTN ProcessorIndex,\r
	183	IN EFI_PERIODIC_CALLBACK PeriodicCallback\r
	184	)\r
	185	{\r
	186	return ManageIdtEntryTable (PeriodicCallback, SYSTEM_TIMER_VECTOR);\r
	187	}\r
	188	\r
	189	/**\r
	190	Registers a function to be called when a given processor exception occurs.\r
	191	\r
	192	This code executes in boot services context.\r
	193	\r
	194	@param This A pointer to the EFI_DEBUG_SUPPORT_PROTOCOL instance.\r
	195	@param ProcessorIndex Specifies which processor the callback function applies to.\r
	196	@param ExceptionCallback A pointer to a function of type EXCEPTION_CALLBACK that is called\r
	197	when the processor exception specified by ExceptionType occurs. \r
	198	@param ExceptionType Specifies which processor exception to hook. \r
	199	\r
	200	@retval EFI_SUCCESS The function completed successfully. \r
	201	@retval EFI_ALREADY_STARTED Non-NULL PeriodicCallback parameter when a callback\r
	202	function was previously registered. \r
	203	@retval EFI_OUT_OF_RESOURCES System has insufficient memory resources to register new callback \r
	204	function.\r
	205	**/\r
	206	EFI_STATUS\r
	207	EFIAPI\r
	208	RegisterExceptionCallback (\r
	209	IN EFI_DEBUG_SUPPORT_PROTOCOL *This,\r
	210	IN UINTN ProcessorIndex,\r
	211	IN EFI_EXCEPTION_CALLBACK ExceptionCallback,\r
	212	IN EFI_EXCEPTION_TYPE ExceptionType\r
	213	)\r
	214	{\r
	215	return ManageIdtEntryTable (ExceptionCallback, ExceptionType);\r
	216	}\r
	217	\r
	218	/**\r
	219	Invalidates processor instruction cache for a memory range. Subsequent execution in this range\r
	220	causes a fresh memory fetch to retrieve code to be executed. \r
	221	\r
	222	@param This A pointer to the EFI_DEBUG_SUPPORT_PROTOCOL instance.\r
	223	@param ProcessorIndex Specifies which processor's instruction cache is to be invalidated.\r
	224	@param Start Specifies the physical base of the memory range to be invalidated. \r
	225	@param Length Specifies the minimum number of bytes in the processor's instruction\r
	226	cache to invalidate. \r
	227	\r
	228	@retval EFI_SUCCESS Always returned.\r
	229	\r
	230	**/\r
	231	EFI_STATUS\r
	232	EFIAPI\r
	233	InvalidateInstructionCache (\r
	234	IN EFI_DEBUG_SUPPORT_PROTOCOL *This,\r
	235	IN UINTN ProcessorIndex,\r
	236	IN VOID *Start,\r
	237	IN UINT64 Length\r
	238	)\r
	239	{\r
	240	AsmWbinvd ();\r
	241	return EFI_SUCCESS;\r
	242	}\r
	243	\r
	244	/**\r
	245	Common piece of code that invokes the registered handlers.\r
	246	\r
	247	This code executes in exception context so no efi calls are allowed.\r
	248	\r
	249	@param ExceptionType Exception type\r
	250	@param ContextRecord System context\r
	251	\r
	252	**/\r
	253	VOID\r
	254	InterruptDistrubutionHub (\r
	255	EFI_EXCEPTION_TYPE ExceptionType,\r
	256	EFI_SYSTEM_CONTEXT_IA32 *ContextRecord\r
	257	)\r
	258	{\r
	259	if (IdtEntryTable[ExceptionType].RegisteredCallback != NULL) {\r
	260	if (ExceptionType != SYSTEM_TIMER_VECTOR) {\r
	261	IdtEntryTable[ExceptionType].RegisteredCallback (ExceptionType, ContextRecord);\r
	262	} else {\r
	263	OrigVector = IdtEntryTable[ExceptionType].OrigVector;\r
	264	IdtEntryTable[ExceptionType].RegisteredCallback (ContextRecord);\r
	265	}\r
	266	}\r
	267	}\r
	268	\r
	269	/**\r
	270	This is the callback that is written to the Loaded Image protocol instance\r
	271	on the image handle. It uninstalls all registered handlers and frees all entry\r
	272	stub memory.\r
	273	\r
	274	@param ImageHandle The firmware allocated handle for the EFI image.\r
	275	\r
	276	@retval EFI_SUCCESS Always.\r
	277	\r
	278	**/\r
	279	EFI_STATUS\r
	280	EFIAPI\r
	281	PlUnloadDebugSupportDriver (\r
	282	IN EFI_HANDLE ImageHandle\r
	283	)\r
	284	{\r
	285	EFI_EXCEPTION_TYPE ExceptionType;\r
	286	\r
	287	for (ExceptionType = 0; ExceptionType < NUM_IDT_ENTRIES; ExceptionType++) {\r
	288	ManageIdtEntryTable (NULL, ExceptionType);\r
	289	//\r
	290	// Free space for each Interrupt Stub precedure.\r
	291	//\r
	292	if (IdtEntryTable[ExceptionType].StubEntry != NULL) {\r
	293	FreePool ((VOID *)(UINTN)IdtEntryTable[ExceptionType].StubEntry);\r
	294	}\r
	295	}\r
	296	\r
	297	FreePool (IdtEntryTable);\r
	298	\r
	299	return EFI_SUCCESS;\r
	300	}\r
	301	\r
	302	/**\r
	303	Initializes driver's handler registration database. \r
	304	\r
	305	This code executes in boot services context.\r
	306	Must be public because it's referenced from DebugSupport.c\r
	307	\r
	308	@retval EFI_UNSUPPORTED If IA32/x64 processor does not support FXSTOR/FXRSTOR instructions,\r
	309	the context save will fail, so these processors are not supported.\r
	310	@retval EFI_OUT_OF_RESOURCES Fails to allocate memory.\r
	311	@retval EFI_SUCCESS Initializes successfully.\r
	312	\r
	313	**/\r
	314	EFI_STATUS\r
	315	PlInitializeDebugSupportDriver (\r
	316	VOID\r
	317	)\r
	318	{\r
	319	EFI_EXCEPTION_TYPE ExceptionType;\r
	320	\r
	321	//\r
	322	// Check whether FxStor instructions are supported.\r
	323	//\r
	324	if (!FxStorSupport ()) {\r
	325	return EFI_UNSUPPORTED;\r
	326	}\r
	327	\r
	328	IdtEntryTable = AllocateZeroPool (sizeof (IDT_ENTRY) * NUM_IDT_ENTRIES);\r
	329	if (IdtEntryTable == NULL) {\r
	330	return EFI_OUT_OF_RESOURCES;\r
	331	}\r
	332	\r
	333	for (ExceptionType = 0; ExceptionType < NUM_IDT_ENTRIES; ExceptionType ++) {\r
	334	IdtEntryTable[ExceptionType].StubEntry = (DEBUG_PROC) (UINTN) AllocatePool (StubSize);\r
	335	if (IdtEntryTable[ExceptionType].StubEntry == NULL) {\r
	336	goto ErrorCleanup;\r
	337	}\r
	338	\r
	339	//\r
	340	// Copy Interrupt stub code.\r
	341	//\r
	342	CopyMem ((VOID *)(UINTN)IdtEntryTable[ExceptionType].StubEntry, InterruptEntryStub, StubSize);\r
	343	}\r
	344	return EFI_SUCCESS;\r
	345	\r
	346	ErrorCleanup:\r
	347	\r
	348	for (ExceptionType = 0; ExceptionType < NUM_IDT_ENTRIES; ExceptionType++) {\r
	349	if (IdtEntryTable[ExceptionType].StubEntry != NULL) {\r
	350	FreePool ((VOID *)(UINTN)IdtEntryTable[ExceptionType].StubEntry);\r
	351	}\r
	352	}\r
	353	FreePool (IdtEntryTable);\r
	354	\r
	355	return EFI_OUT_OF_RESOURCES;\r
	356	}\r