1 /** @file 2 3 Copyright (c) 2008 - 2009, Apple Inc. All rights reserved.<BR> 4 5 This program and the accompanying materials 6 are licensed and made available under the terms and conditions of the BSD License 7 which accompanies this distribution. The full text of the license may be found at 8 http://opensource.org/licenses/bsd-license.php 9 10 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, 11 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED. 12 13 **/ 14 15 #include <Uefi.h> 16 17 #include <Library/BaseLib.h> 18 #include <Library/DebugLib.h> 19 #include <Library/UefiBootServicesTableLib.h> 20 #include <Library/UefiRuntimeServicesTableLib.h> 21 22 #include <Protocol/MonotonicCounter.h> 23 24 UINT64 gCurrentMonotonicCount = 0; 25 26 EFI_STATUS 27 EFIAPI 28 GetNextMonotonicCount ( 29 OUT UINT64 *Count 30 ) 31 { 32 if (Count == NULL) { 33 return EFI_INVALID_PARAMETER; 34 } 35 36 *Count = gCurrentMonotonicCount++; 37 return EFI_SUCCESS; 38 } 39 40 EFI_STATUS 41 EFIAPI 42 GetNextHighMonotonicCount ( 43 OUT UINT32 *HighCount 44 ) 45 { 46 if (HighCount == NULL) { 47 return EFI_INVALID_PARAMETER; 48 } 49 50 gCurrentMonotonicCount += 0x0000000100000000ULL; 51 52 *HighCount = (UINT32)RShiftU64 (gCurrentMonotonicCount, 32) & 0xFFFFFFFF; 53 54 return EFI_SUCCESS; 55 } 56 57 58 EFI_STATUS 59 EFIAPI 60 MonotonicCounterDriverInitialize ( 61 IN EFI_HANDLE ImageHandle, 62 IN EFI_SYSTEM_TABLE *SystemTable 63 ) 64 { 65 EFI_STATUS Status; 66 EFI_HANDLE Handle = NULL; 67 68 // Make sure the Monotonic Counter Architectural Protocol is not already installed in the system 69 ASSERT_PROTOCOL_ALREADY_INSTALLED(NULL, &gEfiMonotonicCounterArchProtocolGuid); 70 71 // Fill in the EFI Boot Services and EFI Runtime Services Monotonic Counter Fields 72 gBS->GetNextMonotonicCount = GetNextMonotonicCount; 73 gRT->GetNextHighMonotonicCount = GetNextHighMonotonicCount; 74 75 // Install the Monotonic Counter Architectural Protocol onto a new handle 76 Status = gBS->InstallMultipleProtocolInterfaces ( 77 &Handle, 78 &gEfiMonotonicCounterArchProtocolGuid, NULL, 79 NULL 80 ); 81 return Status; 82 } 83
