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

/** @file\r
  Produce the UEFI boot service GetNextMonotonicCount() and runtime service\r
  GetNextHighMonotonicCount().\r
\r
Copyright (c) 2006 - 2016, Intel Corporation. All rights reserved.<BR>\r
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 <Uefi.h>\r
\r
#include <Protocol/MonotonicCounter.h>\r
#include <Guid/MtcVendor.h>\r
\r
#include <Library/BaseLib.h>\r
#include <Library/UefiDriverEntryPoint.h>\r
#include <Library/UefiRuntimeLib.h>\r
#include <Library/DebugLib.h>\r
#include <Library/UefiBootServicesTableLib.h>\r
#include <Library/UefiRuntimeServicesTableLib.h>\r
\r
//\r
// The handle to install Monotonic Counter Architctural Protocol\r
//\r
EFI_HANDLE  mMonotonicCounterHandle = NULL;\r
\r
//\r
// The current monotonic counter value\r
//\r
UINT64      mEfiMtc;\r
\r
//\r
// Event to update the monotonic Counter's high part when low part overflows.\r
//\r
EFI_EVENT   mEfiMtcEvent;\r
\r
/**\r
  Returns a monotonically increasing count for the platform.\r
\r
  This function returns a 64-bit value that is numerically larger then the last\r
  time the function was called.\r
  The platform monotonic counter is comprised of two parts: the high 32 bits\r
  and the low 32 bits. The low 32-bit value is volatile and is reset to zero on\r
  every system reset. It is increased by 1 on every call to GetNextMonotonicCount().\r
  The high 32-bit value is nonvolatile and is increased by one on whenever the\r
  system resets or the low 32-bit counter overflows.\r
\r
  @param  Count	                Pointer to returned value.\r
\r
  @retval EFI_SUCCESS           The next monotonic count was returned.\r
  @retval EFI_DEVICE_ERROR      The device is not functioning properly.\r
  @retval EFI_INVALID_PARAMETER Count is NULL.\r
  @retval EFI_UNSUPPORTED       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
  // Cannot 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 low 32-bit counter overflows (MSB bit toggled),\r
  // then signal that the high part needs update now.\r
  //\r
  if ((((UINT32) mEfiMtc) ^ ((UINT32) *Count)) & BIT31) {\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
  whenever GetNextHighMonotonicCount() is called, or whenever the low 32 bit count\r
  (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_SUCCESS           The next high monotonic count was returned.\r
  @retval EFI_INVALID_PARAMETER HighCount is NULL.\r
  @retval EFI_DEVICE_ERROR      The variable could not be saved due to a hardware failure.\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
\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 NV variable to match the new high part\r
  //\r
  return EfiSetVariable (\r
           MTC_VARIABLE_NAME,\r
           &gMtcVendorGuid,\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 counter event handler.  This handler updates the high part of monotonic counter.\r
\r
  @param Event           The event to handle.\r
  @param Context         The event context.\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
  Entry point of monotonic counter driver.\r
\r
  @param  ImageHandle   The image handle of this driver.\r
  @param  SystemTable   The pointer of EFI_SYSTEM_TABLE.\r
\r
  @retval EFI_SUCCESS   The initialization 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 has not been installed in the system yet.\r
  //\r
  ASSERT_PROTOCOL_ALREADY_INSTALLED (NULL, &gEfiMonotonicCounterArchProtocolGuid);\r
\r
  //\r
  // Initialize event to handle low-part overflow\r
  //\r
  Status = gBS->CreateEvent (\r
                  EVT_NOTIFY_SIGNAL,\r
                  TPL_CALLBACK,\r
                  EfiMtcEventHandler,\r
                  NULL,\r
                  &mEfiMtcEvent\r
                  );\r
  ASSERT_EFI_ERROR (Status);\r
\r
  //\r
  // Read the last high part\r
  //\r
  BufferSize = sizeof (UINT32);\r
  Status = EfiGetVariable (\r
             MTC_VARIABLE_NAME,\r
             &gMtcVendorGuid,\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
  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
636578d3	2	Produce the UEFI boot service GetNextMonotonicCount() and runtime service\r
636578d3	3	GetNextHighMonotonicCount().\r
e70d34ca	4	\r
898552fd	5	Copyright (c) 2006 - 2016, Intel Corporation. All rights reserved.<BR>\r
e5eed7d3	6	This program and the accompanying materials\r
e70d34ca	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
636578d3	16	#include <Uefi.h>\r
e70d34ca	17	\r
636578d3	18	#include <Protocol/MonotonicCounter.h>\r
c8ad2d7a	19	#include <Guid/MtcVendor.h>\r
636578d3	20	\r
	21	#include <Library/BaseLib.h>\r
	22	#include <Library/UefiDriverEntryPoint.h>\r
	23	#include <Library/UefiRuntimeLib.h>\r
	24	#include <Library/DebugLib.h>\r
	25	#include <Library/UefiBootServicesTableLib.h>\r
	26	#include <Library/UefiRuntimeServicesTableLib.h>\r
e70d34ca	27	\r
e70d34ca	28	//\r
636578d3	29	// The handle to install Monotonic Counter Architctural Protocol\r
e70d34ca	30	//\r
	31	EFI_HANDLE mMonotonicCounterHandle = NULL;\r
	32	\r
	33	//\r
636578d3	34	// The current monotonic counter value\r
e70d34ca	35	//\r
	36	UINT64 mEfiMtc;\r
	37	\r
	38	//\r
636578d3	39	// Event to update the monotonic Counter's high part when low part overflows.\r
e70d34ca	40	//\r
	41	EFI_EVENT mEfiMtcEvent;\r
	42	\r
52c7a544	43	/**\r
636578d3	44	Returns a monotonically increasing count for the platform.\r
52c7a544	45	\r
636578d3	46	This function returns a 64-bit value that is numerically larger then the last\r
636578d3	47	time the function was called.\r
d089bd5f	48	The platform monotonic counter is comprised of two parts: the high 32 bits\r
636578d3	49	and the low 32 bits. The low 32-bit value is volatile and is reset to zero on\r
	50	every system reset. It is increased by 1 on every call to GetNextMonotonicCount().\r
	51	The high 32-bit value is nonvolatile and is increased by one on whenever the\r
	52	system resets or the low 32-bit counter overflows.\r
52c7a544	53	\r
	54	@param Count Pointer to returned value.\r
	55	\r
636578d3	56	@retval EFI_SUCCESS The next monotonic count was returned.\r
	57	@retval EFI_DEVICE_ERROR The device is not functioning properly.\r
	58	@retval EFI_INVALID_PARAMETER Count is NULL.\r
	59	@retval EFI_UNSUPPORTED This function is called at runtime.\r
52c7a544	60	\r
52c7a544	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
636578d3	71	// Cannot be called after ExitBootServices()\r
e70d34ca	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
636578d3	91	// If the low 32-bit counter overflows (MSB bit toggled),\r
636578d3	92	// then signal that the high part needs update now.\r
e70d34ca	93	//\r
636578d3	94	if ((((UINT32) mEfiMtc) ^ ((UINT32) *Count)) & BIT31) {\r
e70d34ca	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
898552fd SZ	110	The high 32 bit value is non-volatile and is increased by 1 whenever the system resets,\r
	111	whenever GetNextHighMonotonicCount() is called, or whenever the low 32 bit count\r
	112	(returned by GetNextMonoticCount()) overflows.\r
e70d34ca	113	The GetNextMonotonicCount() function is only available at boot services time.\r
	114	If the operating system wishes to extend the platform monotonic counter to runtime,\r
	115	it may do so by utilizing GetNextHighMonotonicCount(). To do this, before calling\r
	116	ExitBootServices() the operating system would call GetNextMonotonicCount() to obtain\r
	117	the current platform monotonic count. The operating system would then provide an\r
	118	interface that returns the next count by:\r
	119	Adding 1 to the last count.\r
	120	Before the lower 32 bits of the count overflows, call GetNextHighMonotonicCount().\r
	121	This will increase the high 32 bits of the platform's non-volatile portion of the monotonic\r
	122	count by 1.\r
	123	\r
	124	This function may only be called at Runtime.\r
	125	\r
52c7a544	126	@param HighCount Pointer to returned value.\r
e70d34ca	127	\r
636578d3	128	@retval EFI_SUCCESS The next high monotonic count was returned.\r
	129	@retval EFI_INVALID_PARAMETER HighCount is NULL.\r
	130	@retval EFI_DEVICE_ERROR The variable could not be saved due to a hardware failure.\r
e70d34ca	131	@retval EFI_OUT_OF_RESOURCES If variable service reports that not enough storage\r
e70d34ca	132	is available to hold the variable and its data.\r
e70d34ca	133	\r
e70d34ca	134	**/\r
e70d34ca	135	EFI_STATUS\r
	136	EFIAPI\r
	137	MonotonicCounterDriverGetNextHighMonotonicCount (\r
	138	OUT UINT32 *HighCount\r
	139	)\r
e70d34ca	140	{\r
	141	EFI_TPL OldTpl;\r
	142	\r
	143	//\r
	144	// Check input parameters\r
	145	//\r
	146	if (HighCount == NULL) {\r
	147	return EFI_INVALID_PARAMETER;\r
	148	}\r
	149	\r
	150	if (!EfiAtRuntime ()) {\r
	151	//\r
	152	// Use a lock if called before ExitBootServices()\r
	153	//\r
	154	OldTpl = gBS->RaiseTPL (TPL_HIGH_LEVEL);\r
	155	*HighCount = (UINT32) RShiftU64 (mEfiMtc, 32) + 1;\r
	156	mEfiMtc = LShiftU64 (*HighCount, 32);\r
	157	gBS->RestoreTPL (OldTpl);\r
	158	} else {\r
	159	*HighCount = (UINT32) RShiftU64 (mEfiMtc, 32) + 1;\r
	160	mEfiMtc = LShiftU64 (*HighCount, 32);\r
	161	}\r
	162	//\r
636578d3	163	// Update the NV variable to match the new high part\r
e70d34ca	164	//\r
e70d34ca	165	return EfiSetVariable (\r
c8ad2d7a LG	166	MTC_VARIABLE_NAME,\r
c8ad2d7a LG	167	&gMtcVendorGuid,\r
e70d34ca	168	EFI_VARIABLE_NON_VOLATILE \| EFI_VARIABLE_RUNTIME_ACCESS \| EFI_VARIABLE_BOOTSERVICE_ACCESS,\r
	169	sizeof (UINT32),\r
	170	HighCount\r
	171	);\r
	172	\r
	173	}\r
	174	\r
52c7a544	175	/**\r
636578d3	176	Monotonic counter event handler. This handler updates the high part of monotonic counter.\r
52c7a544	177	\r
	178	@param Event The event to handle.\r
	179	@param Context The event context.\r
	180	\r
52c7a544	181	**/\r
e70d34ca	182	VOID\r
	183	EFIAPI\r
	184	EfiMtcEventHandler (\r
	185	IN EFI_EVENT Event,\r
	186	IN VOID *Context\r
	187	)\r
e70d34ca	188	{\r
	189	UINT32 HighCount;\r
	190	\r
	191	MonotonicCounterDriverGetNextHighMonotonicCount (&HighCount);\r
	192	}\r
	193	\r
52c7a544	194	/**\r
636578d3	195	Entry point of monotonic counter driver.\r
52c7a544	196	\r
636578d3	197	@param ImageHandle The image handle of this driver.\r
636578d3	198	@param SystemTable The pointer of EFI_SYSTEM_TABLE.\r
52c7a544	199	\r
d41be01a	200	@retval EFI_SUCCESS The initialization is successful.\r
52c7a544	201	\r
52c7a544	202	**/\r
e70d34ca	203	EFI_STATUS\r
	204	EFIAPI\r
	205	MonotonicCounterDriverInitialize (\r
	206	IN EFI_HANDLE ImageHandle,\r
	207	IN EFI_SYSTEM_TABLE *SystemTable\r
	208	)\r
e70d34ca	209	{\r
	210	EFI_STATUS Status;\r
	211	UINT32 HighCount;\r
	212	UINTN BufferSize;\r
	213	\r
	214	//\r
636578d3	215	// Make sure the Monotonic Counter Architectural Protocol has not been installed in the system yet.\r
e70d34ca	216	//\r
	217	ASSERT_PROTOCOL_ALREADY_INSTALLED (NULL, &gEfiMonotonicCounterArchProtocolGuid);\r
	218	\r
	219	//\r
636578d3	220	// Initialize event to handle low-part overflow\r
e70d34ca	221	//\r
	222	Status = gBS->CreateEvent (\r
	223	EVT_NOTIFY_SIGNAL,\r
	224	TPL_CALLBACK,\r
	225	EfiMtcEventHandler,\r
	226	NULL,\r
	227	&mEfiMtcEvent\r
	228	);\r
e70d34ca	229	ASSERT_EFI_ERROR (Status);\r
	230	\r
	231	//\r
	232	// Read the last high part\r
	233	//\r
	234	BufferSize = sizeof (UINT32);\r
	235	Status = EfiGetVariable (\r
c8ad2d7a LG	236	MTC_VARIABLE_NAME,\r
c8ad2d7a LG	237	&gMtcVendorGuid,\r
e70d34ca	238	NULL,\r
	239	&BufferSize,\r
	240	&HighCount\r
	241	);\r
	242	if (EFI_ERROR (Status)) {\r
	243	HighCount = 0;\r
	244	}\r
	245	//\r
	246	// Set the current value\r
	247	//\r
	248	mEfiMtc = LShiftU64 (HighCount, 32);\r
	249	\r
	250	//\r
	251	// Increment the upper 32 bits for this boot\r
	252	// Continue even if it fails. It will only fail if the variable services are\r
	253	// not functional.\r
	254	//\r
636578d3	255	MonotonicCounterDriverGetNextHighMonotonicCount (&HighCount);\r
e70d34ca	256	\r
	257	//\r
	258	// Fill in the EFI Boot Services and EFI Runtime Services Monotonic Counter Fields\r
	259	//\r
	260	gBS->GetNextMonotonicCount = MonotonicCounterDriverGetNextMonotonicCount;\r
	261	gRT->GetNextHighMonotonicCount = MonotonicCounterDriverGetNextHighMonotonicCount;\r
	262	\r
	263	//\r
	264	// Install the Monotonic Counter Architctural Protocol onto a new handle\r
	265	//\r
	266	Status = gBS->InstallMultipleProtocolInterfaces (\r
	267	&mMonotonicCounterHandle,\r
	268	&gEfiMonotonicCounterArchProtocolGuid,\r
	269	NULL,\r
	270	NULL\r
	271	);\r
	272	ASSERT_EFI_ERROR (Status);\r
	273	\r
	274	return EFI_SUCCESS;\r
	275	}\r