/** @file\r
- \r
- Produced the Monotonic Counter Services as defined in the DXE CIS.\r
+ Produce the UEFI boot service GetNextMonotonicCount() and runtime service\r
+ GetNextHighMonotonicCount().\r
\r
Copyright (c) 2006 - 2008, Intel Corporation\r
All rights reserved. This program and the accompanying materials\r
\r
**/\r
\r
+#include <Uefi.h>\r
\r
-#include "MonotonicCounter.h"\r
+#include <Protocol/MonotonicCounter.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 Monotonic Counter Handle\r
+// The handle to install Monotonic Counter Architctural Protocol\r
//\r
EFI_HANDLE mMonotonicCounterHandle = NULL;\r
\r
//\r
-// The current Monotonic count value\r
+// The current monotonic counter value\r
//\r
UINT64 mEfiMtc;\r
\r
//\r
-// Event to use to update the Mtc's high part when wrapping\r
+// Event to update the monotonic Counter's high part when low part overflows.\r
//\r
EFI_EVENT mEfiMtcEvent;\r
\r
//\r
-// EfiMtcName - Variable name of the MTC value\r
+// Name of the variable for the high part of monotonic counter\r
//\r
CHAR16 *mEfiMtcName = (CHAR16 *) L"MTC";\r
\r
//\r
-// EfiMtcGuid - Guid of the MTC value\r
+// Vendor GUID of the variable for the high part of monotonic counter\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
+ Returns a monotonically increasing count for the platform.\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
+ This function returns a 64-bit value that is numerically larger then the last\r
+ time the function was called.\r
+ The platform\92s 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_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
+ @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
EFI_TPL OldTpl;\r
\r
//\r
- // Can not be called after ExitBootServices()\r
+ // Cannot be called after ExitBootServices()\r
//\r
if (EfiAtRuntime ()) {\r
return EFI_UNSUPPORTED;\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
+ // 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)) & 0x80000000) {\r
+ if ((((UINT32) mEfiMtc) ^ ((UINT32) *Count)) & BIT31) {\r
gBS->SignalEvent (mEfiMtcEvent);\r
}\r
\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_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
- @retval EFI_DEVICE_ERROR The variable could not be saved due to a hardware failure.\r
\r
**/\r
EFI_STATUS\r
mEfiMtc = LShiftU64 (*HighCount, 32);\r
}\r
//\r
- // Update the NvRam store to match the new high part\r
+ // Update the NV variable to match the new high part\r
//\r
return EfiSetVariable (\r
mEfiMtcName,\r
}\r
\r
/**\r
- Monotonic count event handler. This handler updates the high monotonic count.\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
- @return None.\r
-\r
**/\r
VOID\r
EFIAPI\r
}\r
\r
/**\r
- The initial function of monotonic counter driver.\r
+ Entry point of monotonic counter driver.\r
\r
- @param ImageHandle The handle of image.\r
- @param SystemTable The pointer to system table.\r
+ @param ImageHandle The image handle of this driver.\r
+ @param SystemTable The pointer of EFI_SYSTEM_TABLE.\r
\r
- @return EFI_SUCCESS The initialize action is successful.\r
+ @return EFI_SUCCESS The initialization is successful.\r
\r
**/\r
EFI_STATUS\r
UINTN BufferSize;\r
\r
//\r
- // Make sure the Monotonic Counter Architectural Protocol is not already installed in the system\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 overflows\r
+ // Initialize event to handle low-part overflow\r
//\r
Status = gBS->CreateEvent (\r
EVT_NOTIFY_SIGNAL,\r
NULL,\r
&mEfiMtcEvent\r
);\r
-\r
ASSERT_EFI_ERROR (Status);\r
\r
//\r
// Continue even if it fails. It will only fail if the variable services are\r
// not functional.\r
//\r
- Status = MonotonicCounterDriverGetNextHighMonotonicCount (&HighCount);\r
+ MonotonicCounterDriverGetNextHighMonotonicCount (&HighCount);\r
\r
//\r
// Fill in the EFI Boot Services and EFI Runtime Services Monotonic Counter Fields\r
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