+++ /dev/null
-/*++\r
-\r
-Copyright (c) 2006 - 2007, 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
-Module Name:\r
-\r
- MonotonicCounter.c\r
-\r
-Abstract:\r
-\r
- Produced the Monotonic Counter Services as defined in the DXE CIS\r
-\r
-Revision History:\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
-// Worker functions\r
-//\r
-STATIC\r
-EFI_STATUS\r
-EFIAPI\r
-MonotonicCounterDriverGetNextMonotonicCount (\r
- OUT UINT64 *Count\r
- )\r
-/*++\r
-\r
-Routine Description:\r
-\r
-Arguments:\r
-\r
-Returns:\r
-\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[out] 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
-STATIC\r
-EFI_STATUS\r
-EFIAPI\r
-MonotonicCounterDriverGetNextHighMonotonicCount (\r
- OUT UINT32 *HighCount\r
- )\r
-/*++\r
-\r
-Routine Description:\r
-\r
-Arguments:\r
-\r
-Returns:\r
-\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
-STATIC\r
-VOID\r
-EFIAPI\r
-EfiMtcEventHandler (\r
- IN EFI_EVENT Event,\r
- IN VOID *Context\r
- )\r
-/*++\r
-\r
-Routine Description:\r
-\r
- Monotonic count event handler. This handler updates the high monotonic count.\r
-\r
-Arguments:\r
-\r
- Event The event to handle\r
- Context The event context\r
-\r
-Returns:\r
-\r
- EFI_SUCCESS The event has been handled properly\r
- EFI_NOT_FOUND An error occurred updating the variable.\r
-\r
---*/\r
-{\r
- UINT32 HighCount;\r
-\r
- MonotonicCounterDriverGetNextHighMonotonicCount (&HighCount);\r
-}\r
-\r
-EFI_STATUS\r
-EFIAPI\r
-MonotonicCounterDriverInitialize (\r
- IN EFI_HANDLE ImageHandle,\r
- IN EFI_SYSTEM_TABLE *SystemTable\r
- )\r
-/*++\r
-\r
-Routine Description:\r
-\r
-Arguments:\r
- (Standard EFI Image entry - EFI_IMAGE_ENTRY_POINT)\r
-\r
-Returns:\r
-\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
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