[mirror_edk2.git] / MdeModulePkg / Core / PiSmmCore / Smi.c

/** @file\r
  SMI management.\r
\r
  Copyright (c) 2009 - 2010, Intel Corporation. All rights reserved.<BR>\r
  This program and the accompanying materials are licensed and made available \r
  under the terms and conditions of the BSD License which accompanies this \r
  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 "PiSmmCore.h"\r
\r
//\r
// SMM_HANDLER - used for each SMM handler\r
//\r
\r
#define SMI_ENTRY_SIGNATURE  SIGNATURE_32('s','m','i','e')\r
\r
 typedef struct {\r
  UINTN       Signature;\r
  LIST_ENTRY  AllEntries;  // All entries\r
\r
  EFI_GUID    HandlerType; // Type of interrupt\r
  LIST_ENTRY  SmiHandlers; // All handlers\r
} SMI_ENTRY;\r
\r
#define SMI_HANDLER_SIGNATURE  SIGNATURE_32('s','m','i','h')\r
\r
 typedef struct {\r
  UINTN                         Signature;\r
  LIST_ENTRY                    Link;        // Link on SMI_ENTRY.SmiHandlers\r
  EFI_SMM_HANDLER_ENTRY_POINT2  Handler;     // The smm handler's entry point\r
  SMI_ENTRY                     *SmiEntry;\r
} SMI_HANDLER;\r
\r
LIST_ENTRY  mRootSmiHandlerList = INITIALIZE_LIST_HEAD_VARIABLE (mRootSmiHandlerList);\r
LIST_ENTRY  mSmiEntryList       = INITIALIZE_LIST_HEAD_VARIABLE (mSmiEntryList);\r
\r
/**\r
  Finds the SMI entry for the requested handler type.\r
\r
  @param  HandlerType            The type of the interrupt\r
  @param  Create                 Create a new entry if not found\r
\r
  @return SMI entry\r
\r
**/\r
SMI_ENTRY  *\r
EFIAPI\r
SmmCoreFindSmiEntry (\r
  IN EFI_GUID  *HandlerType,\r
  IN BOOLEAN   Create\r
  )\r
{\r
  LIST_ENTRY  *Link;\r
  SMI_ENTRY   *Item;\r
  SMI_ENTRY   *SmiEntry;\r
\r
  //\r
  // Search the SMI entry list for the matching GUID\r
  //\r
  SmiEntry = NULL;\r
  for (Link = mSmiEntryList.ForwardLink;\r
       Link != &mSmiEntryList;\r
       Link = Link->ForwardLink) {\r
\r
    Item = CR (Link, SMI_ENTRY, AllEntries, SMI_ENTRY_SIGNATURE);\r
    if (CompareGuid (&Item->HandlerType, HandlerType)) {\r
      //\r
      // This is the SMI entry\r
      //\r
      SmiEntry = Item;\r
      break;\r
    }\r
  }\r
\r
  //\r
  // If the protocol entry was not found and Create is TRUE, then\r
  // allocate a new entry\r
  //\r
  if ((SmiEntry == NULL) && Create) {\r
    SmiEntry = AllocatePool (sizeof(SMI_ENTRY));\r
    if (SmiEntry != NULL) {\r
      //\r
      // Initialize new SMI entry structure\r
      //\r
      SmiEntry->Signature = SMI_ENTRY_SIGNATURE;\r
      CopyGuid ((VOID *)&SmiEntry->HandlerType, HandlerType);\r
      InitializeListHead (&SmiEntry->SmiHandlers);\r
\r
      //\r
      // Add it to SMI entry list\r
      //\r
      InsertTailList (&mSmiEntryList, &SmiEntry->AllEntries);\r
    }\r
  }\r
  return SmiEntry;\r
}\r
\r
/**\r
  Manage SMI of a particular type.\r
\r
  @param  HandlerType    Points to the handler type or NULL for root SMI handlers.\r
  @param  Context        Points to an optional context buffer.\r
  @param  CommBuffer     Points to the optional communication buffer.\r
  @param  CommBufferSize Points to the size of the optional communication buffer.\r
\r
  @retval EFI_SUCCESS                        Interrupt source was processed successfully but not quiesced.\r
  @retval EFI_INTERRUPT_PENDING              One or more SMI sources could not be quiesced.\r
  @retval EFI_WARN_INTERRUPT_SOURCE_PENDING  Interrupt source was not handled or quiesced.\r
  @retval EFI_WARN_INTERRUPT_SOURCE_QUIESCED Interrupt source was handled and quiesced.\r
\r
**/\r
EFI_STATUS\r
EFIAPI\r
SmiManage (\r
  IN     CONST EFI_GUID  *HandlerType,\r
  IN     CONST VOID      *Context         OPTIONAL,\r
  IN OUT VOID            *CommBuffer      OPTIONAL,\r
  IN OUT UINTN           *CommBufferSize  OPTIONAL\r
  )\r
{\r
  LIST_ENTRY   *Link;\r
  LIST_ENTRY   *Head;\r
  SMI_ENTRY    *SmiEntry;\r
  SMI_HANDLER  *SmiHandler;\r
  BOOLEAN      InterruptQuiesced;\r
  EFI_STATUS   Status;\r
  \r
  if (HandlerType == NULL) {\r
    //\r
    // Root SMI handler\r
    //\r
    Status = EFI_WARN_INTERRUPT_SOURCE_PENDING;\r
\r
    Head = &mRootSmiHandlerList;\r
    for (Link = Head->ForwardLink; Link != Head; Link = Link->ForwardLink) {\r
      SmiHandler = CR (Link, SMI_HANDLER, Link, SMI_HANDLER_SIGNATURE);\r
\r
      Status = SmiHandler->Handler (\r
                 (EFI_HANDLE) SmiHandler,\r
                 Context,\r
                 CommBuffer,\r
                 CommBufferSize\r
                 );\r
      if (Status == EFI_SUCCESS || Status == EFI_INTERRUPT_PENDING) {\r
        return Status;\r
      }\r
    }\r
    return Status;\r
  }\r
\r
  //\r
  // Non-root SMI handler\r
  //\r
  SmiEntry = SmmCoreFindSmiEntry ((EFI_GUID *) HandlerType, FALSE);\r
  if (SmiEntry == NULL) {\r
    //\r
    // There is no handler registered for this interrupt source\r
    //\r
    return EFI_WARN_INTERRUPT_SOURCE_PENDING;\r
  }\r
\r
  InterruptQuiesced = FALSE;\r
  Head = &SmiEntry->SmiHandlers;\r
  for (Link = Head->ForwardLink; Link != Head; Link = Link->ForwardLink) {\r
    SmiHandler = CR (Link, SMI_HANDLER, Link, SMI_HANDLER_SIGNATURE);\r
\r
    Status = SmiHandler->Handler (\r
               (EFI_HANDLE) SmiHandler,\r
               Context,\r
               CommBuffer,\r
               CommBufferSize\r
               );\r
\r
    switch (Status) {\r
    case EFI_INTERRUPT_PENDING:\r
      //\r
      // If a handler returns EFI_INTERRUPT_PENDING, the interrupt could not be\r
      // quiesced, then no additional handlers will be processed,\r
      // and EFI_INTERRUPT_PENDING will be returned\r
      //\r
      return EFI_INTERRUPT_PENDING;\r
\r
    case EFI_SUCCESS:\r
      //\r
      // If handler return EFI_SUCCESS, the interrupt was handled and quiesced,\r
      // no other handlers should still be called,\r
      // and EFI_WARN_INTERRUPT_SOURCE_QUIESCED will be returned\r
      //\r
      return EFI_WARN_INTERRUPT_SOURCE_QUIESCED;\r
\r
    case EFI_WARN_INTERRUPT_SOURCE_QUIESCED:\r
      //\r
      // If at least one of the handlers report EFI_WARN_INTERRUPT_SOURCE_QUIESCED,\r
      // then this function will return EFI_WARN_INTERRUPT_SOURCE_QUIESCED\r
      //\r
      InterruptQuiesced = TRUE;\r
      break;\r
\r
    default:\r
      break;\r
    }\r
  }\r
\r
  if (InterruptQuiesced) {\r
    Status = EFI_WARN_INTERRUPT_SOURCE_QUIESCED;\r
  } else {\r
    //\r
    // If no handler report EFI_WARN_INTERRUPT_SOURCE_QUIESCED, then this\r
    // function will return EFI_INTERRUPT_PENDING\r
    //\r
    Status = EFI_INTERRUPT_PENDING;\r
  }\r
  return Status;\r
}\r
\r
/**\r
  Registers a handler to execute within SMM.\r
\r
  @param  Handler        Handler service funtion pointer.\r
  @param  HandlerType    Points to the handler type or NULL for root SMI handlers.\r
  @param  DispatchHandle On return, contains a unique handle which can be used to later unregister the handler function.\r
\r
  @retval EFI_SUCCESS           Handler register success.\r
  @retval EFI_INVALID_PARAMETER Handler or DispatchHandle is NULL.\r
\r
**/\r
EFI_STATUS\r
EFIAPI\r
SmiHandlerRegister (\r
  IN  EFI_SMM_HANDLER_ENTRY_POINT2  Handler,\r
  IN  CONST EFI_GUID                *HandlerType  OPTIONAL,\r
  OUT EFI_HANDLE                    *DispatchHandle\r
  )\r
{\r
  SMI_HANDLER  *SmiHandler;\r
  SMI_ENTRY    *SmiEntry;\r
  LIST_ENTRY   *List;\r
\r
  if (Handler == NULL || DispatchHandle == NULL) {\r
    return EFI_INVALID_PARAMETER;\r
  }\r
\r
  SmiHandler = AllocateZeroPool (sizeof (SMI_HANDLER));\r
  if (SmiHandler == NULL) {\r
    return EFI_OUT_OF_RESOURCES;\r
  }\r
\r
  SmiHandler->Signature = SMI_HANDLER_SIGNATURE;\r
  SmiHandler->Handler = Handler;\r
\r
  if (HandlerType == NULL) {\r
    //\r
    // This is root SMI handler\r
    //\r
    SmiEntry = NULL;\r
    List = &mRootSmiHandlerList;\r
  } else {\r
    //\r
    // None root SMI handler\r
    //\r
    SmiEntry = SmmCoreFindSmiEntry ((EFI_GUID *) HandlerType, TRUE);\r
    if (SmiEntry == NULL) {\r
      return EFI_OUT_OF_RESOURCES;\r
    }\r
\r
    List = &SmiEntry->SmiHandlers;\r
  }\r
\r
  SmiHandler->SmiEntry = SmiEntry;\r
  InsertTailList (List, &SmiHandler->Link);\r
\r
  *DispatchHandle = (EFI_HANDLE) SmiHandler;\r
\r
  return EFI_SUCCESS;\r
}\r
\r
/**\r
  Unregister a handler in SMM.\r
\r
  @param  DispatchHandle  The handle that was specified when the handler was registered.\r
\r
  @retval EFI_SUCCESS           Handler function was successfully unregistered.\r
  @retval EFI_INVALID_PARAMETER DispatchHandle does not refer to a valid handle.\r
\r
**/\r
EFI_STATUS\r
EFIAPI\r
SmiHandlerUnRegister (\r
  IN EFI_HANDLE  DispatchHandle\r
  )\r
{\r
  SMI_HANDLER  *SmiHandler;\r
  SMI_ENTRY    *SmiEntry;\r
\r
  SmiHandler = (SMI_HANDLER *) DispatchHandle;\r
\r
  if (SmiHandler == NULL) {\r
    return EFI_INVALID_PARAMETER;\r
  }\r
\r
  if (SmiHandler->Signature != SMI_HANDLER_SIGNATURE) {\r
    return EFI_INVALID_PARAMETER;\r
  }\r
\r
  SmiEntry = SmiHandler->SmiEntry;\r
\r
  RemoveEntryList (&SmiHandler->Link);\r
  FreePool (SmiHandler);\r
\r
  if (SmiEntry == NULL) {\r
    //\r
    // This is root SMI handler\r
    //\r
    return EFI_SUCCESS;\r
  }\r
\r
  if (IsListEmpty (&SmiEntry->SmiHandlers)) {\r
    //\r
    // No handler registered for this interrupt now, remove the SMI_ENTRY\r
    //\r
    RemoveEntryList (&SmiEntry->AllEntries);\r
\r
    FreePool (SmiEntry);\r
  }\r
\r
  return EFI_SUCCESS;\r
}\r
Commit	Line	Data
e42e9404	1	/** @file\r
	2	SMI management.\r
	3	\r
cd5ebaa0	4	Copyright (c) 2009 - 2010, Intel Corporation. All rights reserved.<BR>\r
e42e9404	5	This program and the accompanying materials are licensed and made available \r
	6	under the terms and conditions of the BSD License which accompanies this \r
	7	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 "PiSmmCore.h"\r
	16	\r
	17	//\r
	18	// SMM_HANDLER - used for each SMM handler\r
	19	//\r
	20	\r
	21	#define SMI_ENTRY_SIGNATURE SIGNATURE_32('s','m','i','e')\r
	22	\r
	23	typedef struct {\r
	24	UINTN Signature;\r
	25	LIST_ENTRY AllEntries; // All entries\r
	26	\r
	27	EFI_GUID HandlerType; // Type of interrupt\r
	28	LIST_ENTRY SmiHandlers; // All handlers\r
	29	} SMI_ENTRY;\r
	30	\r
	31	#define SMI_HANDLER_SIGNATURE SIGNATURE_32('s','m','i','h')\r
	32	\r
	33	typedef struct {\r
	34	UINTN Signature;\r
	35	LIST_ENTRY Link; // Link on SMI_ENTRY.SmiHandlers\r
	36	EFI_SMM_HANDLER_ENTRY_POINT2 Handler; // The smm handler's entry point\r
	37	SMI_ENTRY *SmiEntry;\r
	38	} SMI_HANDLER;\r
	39	\r
	40	LIST_ENTRY mRootSmiHandlerList = INITIALIZE_LIST_HEAD_VARIABLE (mRootSmiHandlerList);\r
	41	LIST_ENTRY mSmiEntryList = INITIALIZE_LIST_HEAD_VARIABLE (mSmiEntryList);\r
	42	\r
	43	/**\r
	44	Finds the SMI entry for the requested handler type.\r
	45	\r
	46	@param HandlerType The type of the interrupt\r
	47	@param Create Create a new entry if not found\r
	48	\r
	49	@return SMI entry\r
	50	\r
	51	**/\r
	52	SMI_ENTRY *\r
	53	EFIAPI\r
	54	SmmCoreFindSmiEntry (\r
	55	IN EFI_GUID *HandlerType,\r
	56	IN BOOLEAN Create\r
	57	)\r
	58	{\r
	59	LIST_ENTRY *Link;\r
	60	SMI_ENTRY *Item;\r
	61	SMI_ENTRY *SmiEntry;\r
	62	\r
	63	//\r
	64	// Search the SMI entry list for the matching GUID\r
	65	//\r
	66	SmiEntry = NULL;\r
	67	for (Link = mSmiEntryList.ForwardLink;\r
	68	Link != &mSmiEntryList;\r
69	Link = Link->ForwardLink) {\r
70	\r
71	Item = CR (Link, SMI_ENTRY, AllEntries, SMI_ENTRY_SIGNATURE);\r
72	if (CompareGuid (&Item->HandlerType, HandlerType)) {\r
73	//\r
74	// This is the SMI entry\r
75	//\r
76	SmiEntry = Item;\r
77	break;\r
78	}\r
79	}\r
80	\r
81	//\r
82	// If the protocol entry was not found and Create is TRUE, then\r
83	// allocate a new entry\r
84	//\r
85	if ((SmiEntry == NULL) && Create) {\r
86	SmiEntry = AllocatePool (sizeof(SMI_ENTRY));\r
87	if (SmiEntry != NULL) {\r
88	//\r
89	// Initialize new SMI entry structure\r
90	//\r
91	SmiEntry->Signature = SMI_ENTRY_SIGNATURE;\r
92	CopyGuid ((VOID *)&SmiEntry->HandlerType, HandlerType);\r
93	InitializeListHead (&SmiEntry->SmiHandlers);\r
94	\r
95	//\r
96	// Add it to SMI entry list\r
97	//\r
98	InsertTailList (&mSmiEntryList, &SmiEntry->AllEntries);\r
99	}\r
100	}\r
101	return SmiEntry;\r
102	}\r
103	\r
104	/**\r
105	Manage SMI of a particular type.\r
106	\r
107	@param HandlerType Points to the handler type or NULL for root SMI handlers.\r
108	@param Context Points to an optional context buffer.\r
109	@param CommBuffer Points to the optional communication buffer.\r
110	@param CommBufferSize Points to the size of the optional communication buffer.\r
111	\r
112	@retval EFI_SUCCESS Interrupt source was processed successfully but not quiesced.\r
113	@retval EFI_INTERRUPT_PENDING One or more SMI sources could not be quiesced.\r
114	@retval EFI_WARN_INTERRUPT_SOURCE_PENDING Interrupt source was not handled or quiesced.\r
115	@retval EFI_WARN_INTERRUPT_SOURCE_QUIESCED Interrupt source was handled and quiesced.\r
116	\r
117	**/\r
118	EFI_STATUS\r
119	EFIAPI\r
120	SmiManage (\r
121	IN CONST EFI_GUID *HandlerType,\r
122	IN CONST VOID *Context OPTIONAL,\r
123	IN OUT VOID *CommBuffer OPTIONAL,\r
124	IN OUT UINTN *CommBufferSize OPTIONAL\r
125	)\r
126	{\r
127	LIST_ENTRY *Link;\r
128	LIST_ENTRY *Head;\r
129	SMI_ENTRY *SmiEntry;\r
130	SMI_HANDLER *SmiHandler;\r
131	BOOLEAN InterruptQuiesced;\r
132	EFI_STATUS Status;\r
133	\r
134	if (HandlerType == NULL) {\r
135	//\r
136	// Root SMI handler\r
137	//\r
138	Status = EFI_WARN_INTERRUPT_SOURCE_PENDING;\r
139	\r
140	Head = &mRootSmiHandlerList;\r
141	for (Link = Head->ForwardLink; Link != Head; Link = Link->ForwardLink) {\r
142	SmiHandler = CR (Link, SMI_HANDLER, Link, SMI_HANDLER_SIGNATURE);\r
143	\r
144	Status = SmiHandler->Handler (\r
145	(EFI_HANDLE) SmiHandler,\r
146	Context,\r
147	CommBuffer,\r
148	CommBufferSize\r
149	);\r
150	if (Status == EFI_SUCCESS \|\| Status == EFI_INTERRUPT_PENDING) {\r
151	return Status;\r
152	}\r
153	}\r
154	return Status;\r
155	}\r
156	\r
157	//\r
158	// Non-root SMI handler\r
159	//\r
160	SmiEntry = SmmCoreFindSmiEntry ((EFI_GUID *) HandlerType, FALSE);\r
161	if (SmiEntry == NULL) {\r
162	//\r
163	// There is no handler registered for this interrupt source\r
164	//\r
165	return EFI_WARN_INTERRUPT_SOURCE_PENDING;\r
166	}\r
167	\r
168	InterruptQuiesced = FALSE;\r
169	Head = &SmiEntry->SmiHandlers;\r
170	for (Link = Head->ForwardLink; Link != Head; Link = Link->ForwardLink) {\r
171	SmiHandler = CR (Link, SMI_HANDLER, Link, SMI_HANDLER_SIGNATURE);\r
172	\r
173	Status = SmiHandler->Handler (\r
174	(EFI_HANDLE) SmiHandler,\r
175	Context,\r
176	CommBuffer,\r
177	CommBufferSize\r
178	);\r
179	\r
180	switch (Status) {\r
181	case EFI_INTERRUPT_PENDING:\r
182	//\r
183	// If a handler returns EFI_INTERRUPT_PENDING, the interrupt could not be\r
184	// quiesced, then no additional handlers will be processed,\r
185	// and EFI_INTERRUPT_PENDING will be returned\r
186	//\r
187	return EFI_INTERRUPT_PENDING;\r
188	\r
189	case EFI_SUCCESS:\r
190	//\r
191	// If handler return EFI_SUCCESS, the interrupt was handled and quiesced,\r
192	// no other handlers should still be called,\r
193	// and EFI_WARN_INTERRUPT_SOURCE_QUIESCED will be returned\r
194	//\r
195	return EFI_WARN_INTERRUPT_SOURCE_QUIESCED;\r
196	\r
197	case EFI_WARN_INTERRUPT_SOURCE_QUIESCED:\r
198	//\r
199	// If at least one of the handlers report EFI_WARN_INTERRUPT_SOURCE_QUIESCED,\r
200	// then this function will return EFI_WARN_INTERRUPT_SOURCE_QUIESCED\r
201	//\r
202	InterruptQuiesced = TRUE;\r
203	break;\r
204	\r
205	default:\r
206	break;\r
207	}\r
208	}\r
209	\r
210	if (InterruptQuiesced) {\r
211	Status = EFI_WARN_INTERRUPT_SOURCE_QUIESCED;\r
212	} else {\r
213	//\r
214	// If no handler report EFI_WARN_INTERRUPT_SOURCE_QUIESCED, then this\r
215	// function will return EFI_INTERRUPT_PENDING\r
216	//\r
217	Status = EFI_INTERRUPT_PENDING;\r
218	}\r
219	return Status;\r
220	}\r
221	\r
222	/**\r
223	Registers a handler to execute within SMM.\r
224	\r
225	@param Handler Handler service funtion pointer.\r
226	@param HandlerType Points to the handler type or NULL for root SMI handlers.\r
227	@param DispatchHandle On return, contains a unique handle which can be used to later unregister the handler function.\r
228	\r
229	@retval EFI_SUCCESS Handler register success.\r
230	@retval EFI_INVALID_PARAMETER Handler or DispatchHandle is NULL.\r
231	\r
232	**/\r
233	EFI_STATUS\r
234	EFIAPI\r
235	SmiHandlerRegister (\r
236	IN EFI_SMM_HANDLER_ENTRY_POINT2 Handler,\r
237	IN CONST EFI_GUID *HandlerType OPTIONAL,\r
238	OUT EFI_HANDLE *DispatchHandle\r
239	)\r
240	{\r
241	SMI_HANDLER *SmiHandler;\r
242	SMI_ENTRY *SmiEntry;\r
243	LIST_ENTRY *List;\r
244	\r
245	if (Handler == NULL \|\| DispatchHandle == NULL) {\r
246	return EFI_INVALID_PARAMETER;\r
247	}\r
248	\r
249	SmiHandler = AllocateZeroPool (sizeof (SMI_HANDLER));\r
250	if (SmiHandler == NULL) {\r
251	return EFI_OUT_OF_RESOURCES;\r
252	}\r
253	\r
254	SmiHandler->Signature = SMI_HANDLER_SIGNATURE;\r
255	SmiHandler->Handler = Handler;\r
256	\r
257	if (HandlerType == NULL) {\r
258	//\r
259	// This is root SMI handler\r
260	//\r
261	SmiEntry = NULL;\r
262	List = &mRootSmiHandlerList;\r
263	} else {\r
264	//\r
265	// None root SMI handler\r
266	//\r
267	SmiEntry = SmmCoreFindSmiEntry ((EFI_GUID *) HandlerType, TRUE);\r
268	if (SmiEntry == NULL) {\r
269	return EFI_OUT_OF_RESOURCES;\r
270	}\r
271	\r
272	List = &SmiEntry->SmiHandlers;\r
273	}\r
274	\r
275	SmiHandler->SmiEntry = SmiEntry;\r
276	InsertTailList (List, &SmiHandler->Link);\r
277	\r
278	*DispatchHandle = (EFI_HANDLE) SmiHandler;\r
279	\r
280	return EFI_SUCCESS;\r
281	}\r
282	\r
283	/**\r
284	Unregister a handler in SMM.\r
285	\r
286	@param DispatchHandle The handle that was specified when the handler was registered.\r
287	\r
288	@retval EFI_SUCCESS Handler function was successfully unregistered.\r
289	@retval EFI_INVALID_PARAMETER DispatchHandle does not refer to a valid handle.\r
290	\r
291	**/\r
292	EFI_STATUS\r
293	EFIAPI\r
294	SmiHandlerUnRegister (\r
295	IN EFI_HANDLE DispatchHandle\r
296	)\r
297	{\r
298	SMI_HANDLER *SmiHandler;\r
299	SMI_ENTRY *SmiEntry;\r
300	\r
301	SmiHandler = (SMI_HANDLER *) DispatchHandle;\r
302	\r
303	if (SmiHandler == NULL) {\r
304	return EFI_INVALID_PARAMETER;\r
305	}\r
306	\r
307	if (SmiHandler->Signature != SMI_HANDLER_SIGNATURE) {\r
308	return EFI_INVALID_PARAMETER;\r
309	}\r
310	\r
311	SmiEntry = SmiHandler->SmiEntry;\r
312	\r
313	RemoveEntryList (&SmiHandler->Link);\r
314	FreePool (SmiHandler);\r
315	\r
316	if (SmiEntry == NULL) {\r
317	//\r
318	// This is root SMI handler\r
319	//\r
320	return EFI_SUCCESS;\r
321	}\r
322	\r
323	if (IsListEmpty (&SmiEntry->SmiHandlers)) {\r
324	//\r
325	// No handler registered for this interrupt now, remove the SMI_ENTRY\r
326	//\r
327	RemoveEntryList (&SmiEntry->AllEntries);\r
328	\r
329	FreePool (SmiEntry);\r
330	}\r
331	\r
332	return EFI_SUCCESS;\r
333	}\r