[mirror_edk2.git] / MdeModulePkg / Universal / MonotonicCounterRuntimeDxe / MonotonicCounter.c

/** @file\r
  \r
  Produced the Monotonic Counter Services as defined in the DXE CIS.\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
\r
#include "MonotonicCounter.h"\r
\r
//\r
// The Monotonic Counter Handle\r
//\r
EFI_HANDLE  mMonotonicCounterHandle = NULL;\r
\r
//\r
// The current Monotonic count value\r
//\r
UINT64      mEfiMtc;\r
\r
//\r
// Event to use to update the Mtc's high part when wrapping\r
//\r
EFI_EVENT   mEfiMtcEvent;\r
\r
//\r
// EfiMtcName - Variable name of the MTC value\r
//\r
CHAR16      *mEfiMtcName = (CHAR16 *) L"MTC";\r
\r
//\r
// EfiMtcGuid - Guid of the MTC value\r
//\r
EFI_GUID    mEfiMtcGuid = { 0xeb704011, 0x1402, 0x11d3, { 0x8e, 0x77, 0x0, 0xa0, 0xc9, 0x69, 0x72, 0x3b } };\r
\r
/**\r
  Returns the low 32 bits of the platform's monotonic counter.\r
\r
  The platform's monotonic counter is comprised of two 32 bit quantities:  \r
  the high 32 bits and the low 32 bits.\r
  During boot service time the low 32 bit value is volatile:  it is reset to\r
  zero on every system reset and is increased by 1 on every call to this function.\r
  This function is only available at boot services time.\r
  Before calling ExitBootServices() the operating system would call this function\r
  to obtain the current platform monotonic count. \r
\r
  @param  Count	                Pointer to returned value.\r
\r
  @retval EFI_INVALID_PARAMETER If Count is NULL.\r
  @retval EFI_SUCCESS           Operation is successful.\r
  @retval EFI_UNSUPPORTED       If this function is called at Runtime.\r
\r
**/\r
EFI_STATUS\r
EFIAPI\r
MonotonicCounterDriverGetNextMonotonicCount (\r
  OUT UINT64  *Count\r
  )\r
{\r
  EFI_TPL OldTpl;\r
\r
  //\r
  // Can not be called after ExitBootServices()\r
  //\r
  if (EfiAtRuntime ()) {\r
    return EFI_UNSUPPORTED;\r
  }\r
  //\r
  // Check input parameters\r
  //\r
  if (Count == NULL) {\r
    return EFI_INVALID_PARAMETER;\r
  }\r
  //\r
  // Update the monotonic counter with a lock\r
  //\r
  OldTpl  = gBS->RaiseTPL (TPL_HIGH_LEVEL);\r
  *Count  = mEfiMtc;\r
  mEfiMtc++;\r
  gBS->RestoreTPL (OldTpl);\r
\r
  //\r
  // If the MSB bit of the low part toggled, then signal that the high\r
  // part needs updated now\r
  //\r
  if ((((UINT32) mEfiMtc) ^ ((UINT32) *Count)) & 0x80000000) {\r
    gBS->SignalEvent (mEfiMtcEvent);\r
  }\r
\r
  return EFI_SUCCESS;\r
}\r
\r
\r
/**\r
  Returns the next high 32 bits of the platform's monotonic counter.\r
\r
  The GetNextHighMonotonicCount() function returns the next high 32 bits\r
  of the platform's monotonic counter. The platform's monotonic counter is\r
  comprised of two 32 bit quantities:  the high 32 bits and the low 32 bits.\r
  During boot service time the low 32 bit value is volatile:  it is reset to\r
  zero on every system reset and is increased by 1 on every call to GetNextMonotonicCount().\r
  The high 32 bit value is non-volatile and is increased by 1 whenever the system resets\r
  or whenever the low 32 bit count [returned by GetNextMonoticCount()] overflows.\r
  The GetNextMonotonicCount() function is only available at boot services time.\r
  If the operating system wishes to extend the platform monotonic counter to runtime,\r
  it may do so by utilizing GetNextHighMonotonicCount().  To do this, before calling\r
  ExitBootServices() the operating system would call GetNextMonotonicCount() to obtain\r
  the current platform monotonic count.  The operating system would then provide an\r
  interface that returns the next count by:\r
    Adding 1 to the last count.\r
    Before the lower 32 bits of the count overflows, call GetNextHighMonotonicCount().\r
    This will increase the high 32 bits of the platform's non-volatile portion of the monotonic\r
    count by 1.\r
\r
  This function may only be called at Runtime.\r
\r
  @param  HighCount	            Pointer to returned value.\r
\r
  @retval EFI_INVALID_PARAMETER If HighCount is NULL.\r
  @retval EFI_SUCCESS           Operation is successful.\r
  @retval EFI_OUT_OF_RESOURCES  If variable service reports that not enough storage\r
                                is available to hold the variable and its data.\r
  @retval EFI_DEVICE_ERROR      The variable could not be saved due to a hardware failure.\r
\r
**/\r
EFI_STATUS\r
EFIAPI\r
MonotonicCounterDriverGetNextHighMonotonicCount (\r
  OUT UINT32  *HighCount\r
  )\r
{\r
  EFI_TPL     OldTpl;\r
\r
  //\r
  // Check input parameters\r
  //\r
  if (HighCount == NULL) {\r
    return EFI_INVALID_PARAMETER;\r
  }\r
\r
  if (!EfiAtRuntime ()) {\r
    //\r
    // Use a lock if called before ExitBootServices()\r
    //\r
    OldTpl      = gBS->RaiseTPL (TPL_HIGH_LEVEL);\r
    *HighCount  = (UINT32) RShiftU64 (mEfiMtc, 32) + 1;\r
    mEfiMtc     = LShiftU64 (*HighCount, 32);\r
    gBS->RestoreTPL (OldTpl);\r
  } else {\r
    *HighCount  = (UINT32) RShiftU64 (mEfiMtc, 32) + 1;\r
    mEfiMtc     = LShiftU64 (*HighCount, 32);\r
  }\r
  //\r
  // Update the NvRam store to match the new high part\r
  //\r
  return EfiSetVariable (\r
           mEfiMtcName,\r
           &mEfiMtcGuid,\r
           EFI_VARIABLE_NON_VOLATILE | EFI_VARIABLE_RUNTIME_ACCESS | EFI_VARIABLE_BOOTSERVICE_ACCESS,\r
           sizeof (UINT32),\r
           HighCount\r
           );\r
\r
}\r
\r
/**\r
  Monotonic count event handler.  This handler updates the high monotonic count.\r
\r
  @param Event           The event to handle.\r
  @param Context         The event context.\r
\r
  @return None.\r
\r
**/\r
VOID\r
EFIAPI\r
EfiMtcEventHandler (\r
  IN EFI_EVENT                Event,\r
  IN VOID                     *Context\r
  )\r
{\r
  UINT32  HighCount;\r
\r
  MonotonicCounterDriverGetNextHighMonotonicCount (&HighCount);\r
}\r
\r
/**\r
  The initial function of monotonic counter driver.\r
\r
  @param  ImageHandle     The handle of image.\r
  @param  SystemTable     The pointer to system table.\r
\r
  @return EFI_SUCCESS     The initialize action is successful.\r
\r
**/\r
EFI_STATUS\r
EFIAPI\r
MonotonicCounterDriverInitialize (\r
  IN EFI_HANDLE        ImageHandle,\r
  IN EFI_SYSTEM_TABLE  *SystemTable\r
  )\r
{\r
  EFI_STATUS  Status;\r
  UINT32      HighCount;\r
  UINTN       BufferSize;\r
\r
  //\r
  // Make sure the Monotonic Counter Architectural Protocol is not already installed in the system\r
  //\r
  ASSERT_PROTOCOL_ALREADY_INSTALLED (NULL, &gEfiMonotonicCounterArchProtocolGuid);\r
\r
  //\r
  // Initialize event to handle overflows\r
  //\r
  Status = gBS->CreateEvent (\r
                  EVT_NOTIFY_SIGNAL,\r
                  TPL_CALLBACK,\r
                  EfiMtcEventHandler,\r
                  NULL,\r
                  &mEfiMtcEvent\r
                  );\r
\r
  ASSERT_EFI_ERROR (Status);\r
\r
  //\r
  // Read the last high part\r
  //\r
  BufferSize = sizeof (UINT32);\r
  Status = EfiGetVariable (\r
             mEfiMtcName,\r
             &mEfiMtcGuid,\r
             NULL,\r
             &BufferSize,\r
             &HighCount\r
             );\r
  if (EFI_ERROR (Status)) {\r
    HighCount = 0;\r
  }\r
  //\r
  // Set the current value\r
  //\r
  mEfiMtc = LShiftU64 (HighCount, 32);\r
\r
  //\r
  // Increment the upper 32 bits for this boot\r
  // Continue even if it fails.  It will only fail if the variable services are\r
  // not functional.\r
  //\r
  Status = MonotonicCounterDriverGetNextHighMonotonicCount (&HighCount);\r
\r
  //\r
  // Fill in the EFI Boot Services and EFI Runtime Services Monotonic Counter Fields\r
  //\r
  gBS->GetNextMonotonicCount      = MonotonicCounterDriverGetNextMonotonicCount;\r
  gRT->GetNextHighMonotonicCount  = MonotonicCounterDriverGetNextHighMonotonicCount;\r
\r
  //\r
  // Install the Monotonic Counter Architctural Protocol onto a new handle\r
  //\r
  Status = gBS->InstallMultipleProtocolInterfaces (\r
                  &mMonotonicCounterHandle,\r
                  &gEfiMonotonicCounterArchProtocolGuid,\r
                  NULL,\r
                  NULL\r
                  );\r
  ASSERT_EFI_ERROR (Status);\r
\r
  return EFI_SUCCESS;\r
}\r
Commit	Line	Data
fb0b259e	1	/** @file\r
52c7a544	2	\r
fb0b259e	3	Produced the Monotonic Counter Services as defined in the DXE CIS.\r
e70d34ca	4	\r
52c7a544	5	Copyright (c) 2006 - 2008, Intel Corporation\r
e70d34ca	6	All rights reserved. This program and the accompanying materials\r
	7	are licensed and made available under the terms and conditions of the BSD License\r
	8	which accompanies this distribution. The full text of the license may be found at\r
	9	http://opensource.org/licenses/bsd-license.php\r
	10	\r
	11	THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r
	12	WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
	13	\r
fb0b259e	14	**/\r
e70d34ca	15	\r
e70d34ca	16	\r
	17	#include "MonotonicCounter.h"\r
	18	\r
	19	//\r
	20	// The Monotonic Counter Handle\r
	21	//\r
	22	EFI_HANDLE mMonotonicCounterHandle = NULL;\r
	23	\r
	24	//\r
	25	// The current Monotonic count value\r
	26	//\r
	27	UINT64 mEfiMtc;\r
	28	\r
	29	//\r
	30	// Event to use to update the Mtc's high part when wrapping\r
	31	//\r
	32	EFI_EVENT mEfiMtcEvent;\r
	33	\r
	34	//\r
	35	// EfiMtcName - Variable name of the MTC value\r
	36	//\r
	37	CHAR16 mEfiMtcName = (CHAR16 ) L"MTC";\r
	38	\r
	39	//\r
	40	// EfiMtcGuid - Guid of the MTC value\r
	41	//\r
	42	EFI_GUID mEfiMtcGuid = { 0xeb704011, 0x1402, 0x11d3, { 0x8e, 0x77, 0x0, 0xa0, 0xc9, 0x69, 0x72, 0x3b } };\r
	43	\r
52c7a544	44	/**\r
	45	Returns the low 32 bits of the platform's monotonic counter.\r
	46	\r
	47	The platform's monotonic counter is comprised of two 32 bit quantities: \r
	48	the high 32 bits and the low 32 bits.\r
	49	During boot service time the low 32 bit value is volatile: it is reset to\r
	50	zero on every system reset and is increased by 1 on every call to this function.\r
	51	This function is only available at boot services time.\r
	52	Before calling ExitBootServices() the operating system would call this function\r
	53	to obtain the current platform monotonic count. \r
	54	\r
	55	@param Count Pointer to returned value.\r
	56	\r
	57	@retval EFI_INVALID_PARAMETER If Count is NULL.\r
	58	@retval EFI_SUCCESS Operation is successful.\r
	59	@retval EFI_UNSUPPORTED If this function is called at Runtime.\r
	60	\r
	61	**/\r
e70d34ca	62	EFI_STATUS\r
	63	EFIAPI\r
	64	MonotonicCounterDriverGetNextMonotonicCount (\r
	65	OUT UINT64 *Count\r
	66	)\r
e70d34ca	67	{\r
	68	EFI_TPL OldTpl;\r
	69	\r
	70	//\r
	71	// Can not be called after ExitBootServices()\r
	72	//\r
	73	if (EfiAtRuntime ()) {\r
	74	return EFI_UNSUPPORTED;\r
	75	}\r
	76	//\r
	77	// Check input parameters\r
	78	//\r
	79	if (Count == NULL) {\r
	80	return EFI_INVALID_PARAMETER;\r
	81	}\r
	82	//\r
	83	// Update the monotonic counter with a lock\r
	84	//\r
	85	OldTpl = gBS->RaiseTPL (TPL_HIGH_LEVEL);\r
	86	*Count = mEfiMtc;\r
	87	mEfiMtc++;\r
	88	gBS->RestoreTPL (OldTpl);\r
	89	\r
	90	//\r
	91	// If the MSB bit of the low part toggled, then signal that the high\r
	92	// part needs updated now\r
	93	//\r
	94	if ((((UINT32) mEfiMtc) ^ ((UINT32) *Count)) & 0x80000000) {\r
	95	gBS->SignalEvent (mEfiMtcEvent);\r
	96	}\r
	97	\r
	98	return EFI_SUCCESS;\r
	99	}\r
	100	\r
	101	\r
	102	/**\r
	103	Returns the next high 32 bits of the platform's monotonic counter.\r
	104	\r
	105	The GetNextHighMonotonicCount() function returns the next high 32 bits\r
	106	of the platform's monotonic counter. The platform's monotonic counter is\r
	107	comprised of two 32 bit quantities: the high 32 bits and the low 32 bits.\r
	108	During boot service time the low 32 bit value is volatile: it is reset to\r
	109	zero on every system reset and is increased by 1 on every call to GetNextMonotonicCount().\r
	110	The high 32 bit value is non-volatile and is increased by 1 whenever the system resets\r
	111	or whenever the low 32 bit count [returned by GetNextMonoticCount()] overflows.\r
	112	The GetNextMonotonicCount() function is only available at boot services time.\r
	113	If the operating system wishes to extend the platform monotonic counter to runtime,\r
	114	it may do so by utilizing GetNextHighMonotonicCount(). To do this, before calling\r
	115	ExitBootServices() the operating system would call GetNextMonotonicCount() to obtain\r
	116	the current platform monotonic count. The operating system would then provide an\r
	117	interface that returns the next count by:\r
	118	Adding 1 to the last count.\r
	119	Before the lower 32 bits of the count overflows, call GetNextHighMonotonicCount().\r
	120	This will increase the high 32 bits of the platform's non-volatile portion of the monotonic\r
	121	count by 1.\r
	122	\r
	123	This function may only be called at Runtime.\r
	124	\r
52c7a544	125	@param HighCount Pointer to returned value.\r
e70d34ca	126	\r
	127	@retval EFI_INVALID_PARAMETER If HighCount is NULL.\r
	128	@retval EFI_SUCCESS Operation is successful.\r
	129	@retval EFI_OUT_OF_RESOURCES If variable service reports that not enough storage\r
	130	is available to hold the variable and its data.\r
	131	@retval EFI_DEVICE_ERROR The variable could not be saved due to a hardware failure.\r
	132	\r
	133	**/\r
e70d34ca	134	EFI_STATUS\r
	135	EFIAPI\r
	136	MonotonicCounterDriverGetNextHighMonotonicCount (\r
	137	OUT UINT32 *HighCount\r
	138	)\r
e70d34ca	139	{\r
	140	EFI_TPL OldTpl;\r
	141	\r
	142	//\r
	143	// Check input parameters\r
	144	//\r
	145	if (HighCount == NULL) {\r
	146	return EFI_INVALID_PARAMETER;\r
	147	}\r
	148	\r
	149	if (!EfiAtRuntime ()) {\r
	150	//\r
	151	// Use a lock if called before ExitBootServices()\r
	152	//\r
	153	OldTpl = gBS->RaiseTPL (TPL_HIGH_LEVEL);\r
	154	*HighCount = (UINT32) RShiftU64 (mEfiMtc, 32) + 1;\r
	155	mEfiMtc = LShiftU64 (*HighCount, 32);\r
	156	gBS->RestoreTPL (OldTpl);\r
	157	} else {\r
	158	*HighCount = (UINT32) RShiftU64 (mEfiMtc, 32) + 1;\r
	159	mEfiMtc = LShiftU64 (*HighCount, 32);\r
	160	}\r
	161	//\r
	162	// Update the NvRam store to match the new high part\r
	163	//\r
	164	return EfiSetVariable (\r
	165	mEfiMtcName,\r
	166	&mEfiMtcGuid,\r
	167	EFI_VARIABLE_NON_VOLATILE \| EFI_VARIABLE_RUNTIME_ACCESS \| EFI_VARIABLE_BOOTSERVICE_ACCESS,\r
	168	sizeof (UINT32),\r
	169	HighCount\r
	170	);\r
	171	\r
	172	}\r
	173	\r
52c7a544	174	/**\r
	175	Monotonic count event handler. This handler updates the high monotonic count.\r
	176	\r
	177	@param Event The event to handle.\r
	178	@param Context The event context.\r
	179	\r
	180	@return None.\r
	181	\r
	182	**/\r
e70d34ca	183	VOID\r
	184	EFIAPI\r
	185	EfiMtcEventHandler (\r
	186	IN EFI_EVENT Event,\r
	187	IN VOID *Context\r
	188	)\r
e70d34ca	189	{\r
	190	UINT32 HighCount;\r
	191	\r
	192	MonotonicCounterDriverGetNextHighMonotonicCount (&HighCount);\r
	193	}\r
	194	\r
52c7a544	195	/**\r
	196	The initial function of monotonic counter driver.\r
	197	\r
	198	@param ImageHandle The handle of image.\r
	199	@param SystemTable The pointer to system table.\r
	200	\r
	201	@return EFI_SUCCESS The initialize action is successful.\r
	202	\r
	203	**/\r
e70d34ca	204	EFI_STATUS\r
	205	EFIAPI\r
	206	MonotonicCounterDriverInitialize (\r
	207	IN EFI_HANDLE ImageHandle,\r
	208	IN EFI_SYSTEM_TABLE *SystemTable\r
	209	)\r
e70d34ca	210	{\r
	211	EFI_STATUS Status;\r
	212	UINT32 HighCount;\r
	213	UINTN BufferSize;\r
	214	\r
	215	//\r
	216	// Make sure the Monotonic Counter Architectural Protocol is not already installed in the system\r
	217	//\r
	218	ASSERT_PROTOCOL_ALREADY_INSTALLED (NULL, &gEfiMonotonicCounterArchProtocolGuid);\r
	219	\r
	220	//\r
	221	// Initialize event to handle overflows\r
	222	//\r
	223	Status = gBS->CreateEvent (\r
	224	EVT_NOTIFY_SIGNAL,\r
	225	TPL_CALLBACK,\r
	226	EfiMtcEventHandler,\r
	227	NULL,\r
	228	&mEfiMtcEvent\r
	229	);\r
	230	\r
	231	ASSERT_EFI_ERROR (Status);\r
	232	\r
	233	//\r
	234	// Read the last high part\r
	235	//\r
	236	BufferSize = sizeof (UINT32);\r
	237	Status = EfiGetVariable (\r
	238	mEfiMtcName,\r
	239	&mEfiMtcGuid,\r
	240	NULL,\r
	241	&BufferSize,\r
	242	&HighCount\r
	243	);\r
	244	if (EFI_ERROR (Status)) {\r
	245	HighCount = 0;\r
	246	}\r
	247	//\r
	248	// Set the current value\r
	249	//\r
	250	mEfiMtc = LShiftU64 (HighCount, 32);\r
	251	\r
	252	//\r
	253	// Increment the upper 32 bits for this boot\r
	254	// Continue even if it fails. It will only fail if the variable services are\r
	255	// not functional.\r
	256	//\r
	257	Status = MonotonicCounterDriverGetNextHighMonotonicCount (&HighCount);\r
	258	\r
	259	//\r
	260	// Fill in the EFI Boot Services and EFI Runtime Services Monotonic Counter Fields\r
	261	//\r
	262	gBS->GetNextMonotonicCount = MonotonicCounterDriverGetNextMonotonicCount;\r
	263	gRT->GetNextHighMonotonicCount = MonotonicCounterDriverGetNextHighMonotonicCount;\r
	264	\r
	265	//\r
	266	// Install the Monotonic Counter Architctural Protocol onto a new handle\r
	267	//\r
	268	Status = gBS->InstallMultipleProtocolInterfaces (\r
	269	&mMonotonicCounterHandle,\r
	270	&gEfiMonotonicCounterArchProtocolGuid,\r
	271	NULL,\r
	272	NULL\r
	273	);\r
274	ASSERT_EFI_ERROR (Status);\r
275	\r
276	return EFI_SUCCESS;\r
277	}\r