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/** @file
Copyright (c) 2008 - 2009, Apple Inc. All rights reserved.<BR>
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
#include <Uefi.h>
#include <Library/BaseLib.h>
#include <Library/DebugLib.h>
#include <Library/UefiBootServicesTableLib.h>
#include <Library/UefiRuntimeServicesTableLib.h>
#include <Protocol/MonotonicCounter.h>
UINT64 gCurrentMonotonicCount = 0;
EFI_STATUS
EFIAPI
GetNextMonotonicCount (
OUT UINT64 *Count
)
{
if (Count == NULL) {
return EFI_INVALID_PARAMETER;
}
*Count = gCurrentMonotonicCount++;
return EFI_SUCCESS;
}
EFI_STATUS
EFIAPI
GetNextHighMonotonicCount (
OUT UINT32 *HighCount
)
{
if (HighCount == NULL) {
return EFI_INVALID_PARAMETER;
}
gCurrentMonotonicCount += 0x0000000100000000ULL;
*HighCount = (UINT32)RShiftU64 (gCurrentMonotonicCount, 32) & 0xFFFFFFFF;
return EFI_SUCCESS;
}
EFI_STATUS
EFIAPI
MonotonicCounterDriverInitialize (
IN EFI_HANDLE ImageHandle,
IN EFI_SYSTEM_TABLE *SystemTable
)
{
EFI_STATUS Status;
EFI_HANDLE Handle = NULL;
// Make sure the Monotonic Counter Architectural Protocol is not already installed in the system
ASSERT_PROTOCOL_ALREADY_INSTALLED(NULL, &gEfiMonotonicCounterArchProtocolGuid);
// Fill in the EFI Boot Services and EFI Runtime Services Monotonic Counter Fields
gBS->GetNextMonotonicCount = GetNextMonotonicCount;
gRT->GetNextHighMonotonicCount = GetNextHighMonotonicCount;
// Install the Monotonic Counter Architectural Protocol onto a new handle
Status = gBS->InstallMultipleProtocolInterfaces (
&Handle,
&gEfiMonotonicCounterArchProtocolGuid, NULL,
NULL
);
return Status;
}
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