/** @file
  Debug Agent library implementation.

  Copyright (c) 2010 - 2018, Intel Corporation. All rights reserved.<BR>
  SPDX-License-Identifier: BSD-2-Clause-Patent

**/

#include "SmmDebugAgentLib.h"

DEBUG_AGENT_MAILBOX       *mMailboxPointer = NULL;
DEBUG_AGENT_MAILBOX       mLocalMailbox;
UINTN                     mSavedDebugRegisters[6];
IA32_IDT_GATE_DESCRIPTOR  mIdtEntryTable[33];
BOOLEAN                   mSkipBreakpoint      = FALSE;
BOOLEAN                   mSmmDebugIdtInitFlag = FALSE;
BOOLEAN                   mApicTimerRestore    = FALSE;
BOOLEAN                   mPeriodicMode;
UINT32                    mTimerCycle;
UINTN                     mApicTimerDivisor;
UINT8                     mVector;

CHAR8  mWarningMsgIgnoreSmmEntryBreak[] = "Ignore smmentrybreak setting for SMI issued during DXE debugging!\r\n";

/**
  Check if debug agent support multi-processor.

  @retval TRUE    Multi-processor is supported.
  @retval FALSE   Multi-processor is not supported.

**/
BOOLEAN
MultiProcessorDebugSupport (
  VOID
  )
{
  return FALSE;
}

/**
  Read the Attach/Break-in symbols from the debug port.

  @param[in]  Handle         Pointer to Debug Port handle.
  @param[out] BreakSymbol    Returned break symbol.

  @retval EFI_SUCCESS        Read the symbol in BreakSymbol.
  @retval EFI_NOT_FOUND      No read the break symbol.

**/
EFI_STATUS
DebugReadBreakSymbol (
  IN  DEBUG_PORT_HANDLE  Handle,
  OUT UINT8              *BreakSymbol
  )
{
  //
  // Smm instance has no debug timer to poll break symbol.
  //
  return EFI_NOT_FOUND;
}

/**
  Get the pointer to Mailbox from the GUIDed HOB.

  @return Pointer to Mailbox.

**/
DEBUG_AGENT_MAILBOX *
GetMailboxFromHob (
  VOID
  )
{
  EFI_HOB_GUID_TYPE    *GuidHob;
  UINT64               *MailboxLocation;
  DEBUG_AGENT_MAILBOX  *Mailbox;

  GuidHob = GetFirstGuidHob (&gEfiDebugAgentGuid);
  if (GuidHob == NULL) {
    return NULL;
  }

  MailboxLocation = (UINT64 *)(GET_GUID_HOB_DATA (GuidHob));
  Mailbox         = (DEBUG_AGENT_MAILBOX *)(UINTN)(*MailboxLocation);
  VerifyMailboxChecksum (Mailbox);

  return Mailbox;
}

/**
  Get Debug Agent Mailbox pointer.

  @return Mailbox pointer.

**/
DEBUG_AGENT_MAILBOX *
GetMailboxPointer (
  VOID
  )
{
  VerifyMailboxChecksum (mMailboxPointer);
  return mMailboxPointer;
}

/**
  Get debug port handle.

  @return Debug port handle.

**/
DEBUG_PORT_HANDLE
GetDebugPortHandle (
  VOID
  )
{
  return (DEBUG_PORT_HANDLE)(UINTN)(GetMailboxPointer ()->DebugPortHandle);
}

/**
  Store debug register when SMI exit.

**/
VOID
SaveDebugRegister (
  VOID
  )
{
  mSavedDebugRegisters[0] = AsmReadDr0 ();
  mSavedDebugRegisters[1] = AsmReadDr1 ();
  mSavedDebugRegisters[2] = AsmReadDr2 ();
  mSavedDebugRegisters[3] = AsmReadDr3 ();
  mSavedDebugRegisters[4] = AsmReadDr6 ();
  mSavedDebugRegisters[5] = AsmReadDr7 ();
}

/**
  Restore debug register when SMI exit.

**/
VOID
RestoreDebugRegister (
  VOID
  )
{
  AsmWriteDr7 (0);
  AsmWriteDr0 (mSavedDebugRegisters[0]);
  AsmWriteDr1 (mSavedDebugRegisters[1]);
  AsmWriteDr2 (mSavedDebugRegisters[2]);
  AsmWriteDr3 (mSavedDebugRegisters[3]);
  AsmWriteDr6 (mSavedDebugRegisters[4]);
  AsmWriteDr7 (mSavedDebugRegisters[5]);
}

/**
  Initialize debug agent.

  This function is used to set up debug environment for source level debug
  in SMM code.

  If InitFlag is DEBUG_AGENT_INIT_SMM, it will override IDT table entries
  and initialize debug port. It will get debug agent Mailbox from GUIDed HOB,
  it it exists, debug agent wiil copied it into the local Mailbox in SMM space.
  it will override IDT table entries and initialize debug port. Context must
  point to a BOOLEAN if it's not NULL, which indicates SMM Debug Agent supported
  or not.
  If InitFlag is DEBUG_AGENT_INIT_ENTER_SMI, debug agent will save Debug
  Registers and get local Mailbox in SMM space. Context will be NULL.
  If InitFlag is DEBUG_AGENT_INIT_EXIT_SMI, debug agent will restore Debug
  Registers. Context will be NULL.

  @param[in] InitFlag     Init flag is used to decide initialize process.
  @param[in] Context      Context needed according to InitFlag.
  @param[in] Function     Continue function called by debug agent library; it was
                          optional.

**/
VOID
EFIAPI
InitializeDebugAgent (
  IN UINT32                InitFlag,
  IN VOID                  *Context  OPTIONAL,
  IN DEBUG_AGENT_CONTINUE  Function  OPTIONAL
  )
{
  EFI_STATUS                Status;
  UINT64                    DebugPortHandle;
  IA32_IDT_GATE_DESCRIPTOR  IdtEntry[33];
  IA32_DESCRIPTOR           IdtDescriptor;
  IA32_DESCRIPTOR           *Ia32Idtr;
  IA32_IDT_ENTRY            *Ia32IdtEntry;
  IA32_DESCRIPTOR           Idtr;
  UINT16                    IdtEntryCount;
  DEBUG_AGENT_MAILBOX       *Mailbox;
  UINT64                    *MailboxLocation;
  UINT32                    DebugTimerFrequency;

  switch (InitFlag) {
    case DEBUG_AGENT_INIT_SMM:
      //
      // Install configuration table for persisted vector handoff info
      //
      Status = gSmst->SmmInstallConfigurationTable (
                        gSmst,
                        &gEfiVectorHandoffTableGuid,
                        (VOID *)&mVectorHandoffInfoDebugAgent[0],
                        sizeof (EFI_VECTOR_HANDOFF_INFO) * mVectorHandoffInfoCount
                        );
      if (EFI_ERROR (Status)) {
        DEBUG ((DEBUG_ERROR, "DebugAgent: Cannot install configuration table for persisted vector handoff info!\n"));
        if (Context != NULL) {
          *(BOOLEAN *)Context = FALSE;
        }

        CpuDeadLoop ();
      }

      //
      // Check if Debug Agent initialized in DXE phase
      //
      Status = EfiGetSystemConfigurationTable (&gEfiDebugAgentGuid, (VOID **)&Mailbox);
      if ((Status == EFI_SUCCESS) && (Mailbox != NULL)) {
        VerifyMailboxChecksum (Mailbox);
        mMailboxPointer = Mailbox;
        if (Context != NULL) {
          *(BOOLEAN *)Context = TRUE;
        }

        break;
      }

      //
      // Check if Debug Agent initialized in SEC/PEI phase
      //
      Mailbox = GetMailboxFromHob ();
      if (Mailbox != NULL) {
        mMailboxPointer = Mailbox;
        if (Context != NULL) {
          *(BOOLEAN *)Context = TRUE;
        }

        break;
      }

      //
      // Debug Agent was not initialized before, use the local mailbox.
      //
      ZeroMem (&mLocalMailbox, sizeof (DEBUG_AGENT_MAILBOX));
      Mailbox = &mLocalMailbox;
      //
      // Save original IDT entries
      //
      AsmReadIdtr (&IdtDescriptor);
      CopyMem (&IdtEntry, (VOID *)IdtDescriptor.Base, 33 * sizeof (IA32_IDT_GATE_DESCRIPTOR));
      //
      // Initialized Debug Agent
      //
      InitializeDebugIdt ();
      //
      // Initialize Debug Timer hardware and save its frequency
      //
      InitializeDebugTimer (&DebugTimerFrequency, TRUE);
      UpdateMailboxContent (Mailbox, DEBUG_MAILBOX_DEBUG_TIMER_FREQUENCY, DebugTimerFrequency);

      DebugPortHandle = (UINT64)(UINTN)DebugPortInitialize ((DEBUG_PORT_HANDLE)(UINTN)Mailbox->DebugPortHandle, NULL);
      UpdateMailboxContent (Mailbox, DEBUG_MAILBOX_DEBUG_PORT_HANDLE_INDEX, DebugPortHandle);
      mMailboxPointer = Mailbox;
      //
      // Trigger one software interrupt to inform HOST
      //
      TriggerSoftInterrupt (SYSTEM_RESET_SIGNATURE);

      SetDebugFlag (DEBUG_AGENT_FLAG_MEMORY_READY, 1);
      //
      // Memory has been ready
      //
      if (IsHostAttached ()) {
        //
        // Trigger one software interrupt to inform HOST
        //
        TriggerSoftInterrupt (MEMORY_READY_SIGNATURE);
      }
      //
      // Restore saved IDT entries
      //
      CopyMem ((VOID *)IdtDescriptor.Base, &IdtEntry, 33 * sizeof (IA32_IDT_GATE_DESCRIPTOR));

      if (Context != NULL) {
        *(BOOLEAN *)Context = TRUE;
      }

      break;

    case DEBUG_AGENT_INIT_ENTER_SMI:
      SaveDebugRegister ();
      if (!mSmmDebugIdtInitFlag) {
        //
        // We only need to initialize Debug IDT table at first SMI entry
        // after SMM relocation.
        //
        InitializeDebugIdt ();
        mSmmDebugIdtInitFlag = TRUE;
      }

      //
      // Check if CPU APIC Timer is working, otherwise initialize it.
      //
      InitializeLocalApicSoftwareEnable (TRUE);
      GetApicTimerState (&mApicTimerDivisor, &mPeriodicMode, &mVector);
      mTimerCycle = GetApicTimerInitCount ();
      if (!mPeriodicMode || (mTimerCycle == 0)) {
        mApicTimerRestore = TRUE;
        InitializeDebugTimer (NULL, FALSE);
      }

      Mailbox = GetMailboxPointer ();
      if (GetDebugFlag (DEBUG_AGENT_FLAG_AGENT_IN_PROGRESS) == 1) {
        //
        // If Debug Agent has been communication state with HOST, we need skip
        // any break points set in SMM, set Skip Breakpoint flag
        //
        mSkipBreakpoint = TRUE;
      }

      if (GetDebugFlag (DEBUG_AGENT_FLAG_BREAK_ON_NEXT_SMI) == 1) {
        if (mSkipBreakpoint) {
          //
          // Print warning message if ignore smm entry break
          //
          DebugPortWriteBuffer (
            (DEBUG_PORT_HANDLE)(UINTN)Mailbox->DebugPortHandle,
            (UINT8 *)mWarningMsgIgnoreSmmEntryBreak,
            AsciiStrLen (mWarningMsgIgnoreSmmEntryBreak)
            );
        } else {
          //
          // If SMM entry break is set, SMM code will be break at here.
          //
          CpuBreakpoint ();
        }
      }

      break;

    case DEBUG_AGENT_INIT_EXIT_SMI:
      Mailbox = GetMailboxPointer ();
      //
      // Clear Skip Breakpoint flag
      //
      mSkipBreakpoint = FALSE;
      RestoreDebugRegister ();
      //
      // Restore APIC Timer
      //
      if (mApicTimerRestore) {
        InitializeApicTimer (mApicTimerDivisor, mTimerCycle, mPeriodicMode, mVector);
        mApicTimerRestore = FALSE;
      }

      break;

    case DEBUG_AGENT_INIT_THUNK_PEI_IA32TOX64:
      if (Context == NULL) {
        DEBUG ((DEBUG_ERROR, "DebugAgent: Input parameter Context cannot be NULL!\n"));
        CpuDeadLoop ();
      } else {
        Ia32Idtr        =  (IA32_DESCRIPTOR *)Context;
        Ia32IdtEntry    = (IA32_IDT_ENTRY *)(Ia32Idtr->Base);
        MailboxLocation = (UINT64 *)((UINTN)Ia32IdtEntry[DEBUG_MAILBOX_VECTOR].Bits.OffsetLow +
                                     ((UINTN)Ia32IdtEntry[DEBUG_MAILBOX_VECTOR].Bits.OffsetHigh << 16));
        mMailboxPointer = (DEBUG_AGENT_MAILBOX *)(UINTN)(*MailboxLocation);
        VerifyMailboxChecksum (mMailboxPointer);
        //
        // Get original IDT address and size.
        //
        AsmReadIdtr ((IA32_DESCRIPTOR *)&Idtr);
        IdtEntryCount = (UINT16)((Idtr.Limit + 1) / sizeof (IA32_IDT_GATE_DESCRIPTOR));
        if (IdtEntryCount < 33) {
          Idtr.Limit = (UINT16)(sizeof (IA32_IDT_GATE_DESCRIPTOR) * 33 - 1);
          Idtr.Base  = (UINTN)&mIdtEntryTable;
          ZeroMem (&mIdtEntryTable, Idtr.Limit + 1);
          AsmWriteIdtr ((IA32_DESCRIPTOR *)&Idtr);
        }

        InitializeDebugIdt ();
        //
        // Initialize Debug Timer hardware and save its frequency
        //
        InitializeDebugTimer (&DebugTimerFrequency, TRUE);
        UpdateMailboxContent (mMailboxPointer, DEBUG_MAILBOX_DEBUG_TIMER_FREQUENCY, DebugTimerFrequency);
        //
        // Enable Debug Timer interrupt and CPU interrupt
        //
        SaveAndSetDebugTimerInterrupt (TRUE);
        EnableInterrupts ();
      }
      break;

    default:
      //
      // Only DEBUG_AGENT_INIT_PREMEM_SEC and DEBUG_AGENT_INIT_POSTMEM_SEC are allowed for this
      // Debug Agent library instance.
      //
      DEBUG ((DEBUG_ERROR, "Debug Agent: The InitFlag value is not allowed!\n"));
      CpuDeadLoop ();
      break;
  }
}
