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