/** @file
  Semaphore mechanism to indicate to the BSP that an AP has exited SMM
  after SMBASE relocation.

  Copyright (c) 2024, Intel Corporation. All rights reserved.<BR>
  SPDX-License-Identifier: BSD-2-Clause-Patent

**/

#include "InternalSmmRelocationLib.h"

X86_ASSEMBLY_PATCH_LABEL  gPatchSmmRelocationOriginalAddressPtr32;
X86_ASSEMBLY_PATCH_LABEL  gPatchRebasedFlagAddr32;

UINTN             mSmmRelocationOriginalAddress;
volatile BOOLEAN  *mRebasedFlag;
SPIN_LOCK         mSmmRelocationSemaphore;

/**
AP Semaphore operation in 32-bit mode while BSP runs in 64-bit mode.
**/
VOID
SmmRelocationSemaphoreComplete32 (
  VOID
  );

/**
  Acquire the SMM Relocation Semaphore.
**/
VOID
EFIAPI
AcquireSmmRelocationSemaphore (
  VOID
  )
{
  AcquireSpinLock (&mSmmRelocationSemaphore);
}

/**
  Release the SMM Relocation Semaphore.
**/
VOID
EFIAPI
ReleaseSmmRelocationSemaphore (
  VOID
  )
{
  ReleaseSpinLock (&mSmmRelocationSemaphore);
}

/**
  Hook return address of SMM Save State so that semaphore code
  can be executed immediately after AP exits SMM to indicate to
  the BSP that an AP has exited SMM after SMBASE relocation.

  @param[in] RebasedFlag  A pointer to a flag that is set to TRUE
                          immediately after AP exits SMM.

**/
VOID
SemaphoreHook (
  IN volatile BOOLEAN  *RebasedFlag
  )
{
  SMRAM_SAVE_STATE_MAP  *CpuState;
  UINTN                 TempValue;

  mRebasedFlag = RebasedFlag;
  PatchInstructionX86 (
    gPatchRebasedFlagAddr32,
    (UINT32)(UINTN)mRebasedFlag,
    4
    );

  CpuState = (SMRAM_SAVE_STATE_MAP *)(UINTN)(SMM_DEFAULT_SMBASE + SMRAM_SAVE_STATE_MAP_OFFSET);
  AcquireSmmRelocationSemaphore ();
  mSmmRelocationOriginalAddress = HookReturnFromSmm (
                                    CpuState,
                                    (UINT64)(UINTN)&SmmRelocationSemaphoreComplete32,
                                    (UINT64)(UINTN)&SmmRelocationSemaphoreComplete
                                    );

  //
  // Use temp value to fix ICC compiler warning
  //
  TempValue = (UINTN)&mSmmRelocationOriginalAddress;
  PatchInstructionX86 (
    gPatchSmmRelocationOriginalAddressPtr32,
    (UINT32)TempValue,
    4
    );
}
