GdbStub.c

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#include <GdbStubInternal.h>
#include <Protocol/DebugPort.h>
 
UINTN  gMaxProcessorIndex = 0;
 
//
// Buffers for basic gdb communication
//
CHAR8  gInBuffer[MAX_BUF_SIZE];
CHAR8  gOutBuffer[MAX_BUF_SIZE];
 
// Assume gdb does a "qXfer:libraries:read::offset,length" when it connects so we can default
// this value to FALSE. Since gdb can reconnect its self a global default is not good enough
BOOLEAN    gSymbolTableUpdate = FALSE;
EFI_EVENT  gEvent;
VOID       *gGdbSymbolEventHandlerRegistration = NULL;
 
//
// Globals for returning XML from qXfer:libraries:read packet
//
UINTN                              gPacketqXferLibraryOffset = 0;
UINTN                              gEfiDebugImageTableEntry  = 0;
EFI_DEBUG_IMAGE_INFO_TABLE_HEADER  *gDebugImageTableHeader   = NULL;
EFI_DEBUG_IMAGE_INFO               *gDebugTable              = NULL;
CHAR8                              gXferLibraryBuffer[2000];
 
GLOBAL_REMOVE_IF_UNREFERENCED CONST CHAR8  mHexToStr[] = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' };
 
VOID
EFIAPI
GdbSymbolEventHandler (
  IN  EFI_EVENT  Event,
  IN  VOID       *Context
  )
{
}
 
EFI_STATUS
EFIAPI
GdbStubEntry (
  IN EFI_HANDLE        ImageHandle,
  IN EFI_SYSTEM_TABLE  *SystemTable
  )
{
  EFI_STATUS                  Status;
  EFI_DEBUG_SUPPORT_PROTOCOL  *DebugSupport;
  UINTN                       HandleCount;
  EFI_HANDLE                  *Handles;
  UINTN                       Index;
  UINTN                       Processor;
  BOOLEAN                     IsaSupported;
 
  Status = EfiGetSystemConfigurationTable (&gEfiDebugImageInfoTableGuid, (VOID **)&gDebugImageTableHeader);
  if (EFI_ERROR (Status)) {
    gDebugImageTableHeader = NULL;
  }
 
  Status = gBS->LocateHandleBuffer (
                  ByProtocol,
                  &gEfiDebugSupportProtocolGuid,
                  NULL,
                  &HandleCount,
                  &Handles
                  );
  if (EFI_ERROR (Status)) {
    DEBUG ((DEBUG_ERROR, "Debug Support Protocol not found\n"));
 
    return Status;
  }
 
  DebugSupport = NULL;
  IsaSupported = FALSE;
  do {
    HandleCount--;
    Status = gBS->HandleProtocol (
                    Handles[HandleCount],
                    &gEfiDebugSupportProtocolGuid,
                    (VOID **)&DebugSupport
                    );
    if (!EFI_ERROR (Status)) {
      if (CheckIsa (DebugSupport->Isa)) {
        // We found what we are looking for so break out of the loop
        IsaSupported = TRUE;
        break;
      }
    }
  } while (HandleCount > 0);
 
  FreePool (Handles);
 
  if (!IsaSupported) {
    DEBUG ((DEBUG_ERROR, "Debug Support Protocol does not support our ISA\n"));
 
    return EFI_NOT_FOUND;
  }
 
  Status = DebugSupport->GetMaximumProcessorIndex (DebugSupport, &gMaxProcessorIndex);
  ASSERT_EFI_ERROR (Status);
 
  DEBUG ((DEBUG_INFO, "Debug Support Protocol ISA %x\n", DebugSupport->Isa));
  DEBUG ((DEBUG_INFO, "Debug Support Protocol Processor Index %d\n", gMaxProcessorIndex));
 
  // Call processor-specific init routine
  InitializeProcessor ();
 
  for (Processor = 0; Processor <= gMaxProcessorIndex; Processor++) {
    for (Index = 0; Index < MaxEfiException (); Index++) {
      Status = DebugSupport->RegisterExceptionCallback (DebugSupport, Processor, GdbExceptionHandler, gExceptionType[Index].Exception);
      ASSERT_EFI_ERROR (Status);
    }
 
    //
    // Current edk2 DebugPort is not interrupt context safe so we can not use it
    //
    Status = DebugSupport->RegisterPeriodicCallback (DebugSupport, Processor, GdbPeriodicCallBack);
    ASSERT_EFI_ERROR (Status);
  }
 
  //
  // This even fires every time an image is added. This allows the stub to know when gdb needs
  // to update the symbol table.
  //
  Status = gBS->CreateEvent (
                  EVT_NOTIFY_SIGNAL,
                  TPL_CALLBACK,
                  GdbSymbolEventHandler,
                  NULL,
                  &gEvent
                  );
  ASSERT_EFI_ERROR (Status);
 
  //
  // Register for protocol notifications on this event
  //
  Status = gBS->RegisterProtocolNotify (
                  &gEfiLoadedImageProtocolGuid,
                  gEvent,
                  &gGdbSymbolEventHandlerRegistration
                  );
  ASSERT_EFI_ERROR (Status);
 
  if (PcdGetBool (PcdGdbSerial)) {
    GdbInitializeSerialConsole ();
  }
 
  return EFI_SUCCESS;
}
 
VOID
TransferFromInBufToMem (
  IN    UINTN          Length,
  IN    unsigned char  *Address,
  IN    CHAR8          *NewData
  )
{
  CHAR8  c1;
  CHAR8  c2;
 
  while (Length-- > 0) {
    c1 = (CHAR8)HexCharToInt (*NewData++);
    c2 = (CHAR8)HexCharToInt (*NewData++);
 
    if ((c1 < 0) || (c2 < 0)) {
      Print ((CHAR16 *)L"Bad message from write to memory..\n");
      SendError (GDB_EBADMEMDATA);
      return;
    }
 
    *Address++ = (UINT8)((c1 << 4) + c2);
  }
 
  SendSuccess ();
}
 
VOID
TransferFromMemToOutBufAndSend (
  IN    UINTN          Length,
  IN    unsigned char  *Address
  )
{
  // there are Length bytes and every byte is represented as 2 hex chars
  CHAR8  OutBuffer[MAX_BUF_SIZE];
  CHAR8  *OutBufPtr;              // pointer to the output buffer
  CHAR8  Char;
 
  if (ValidateAddress (Address) == FALSE) {
    SendError (14);
    return;
  }
 
  OutBufPtr = OutBuffer;
  while (Length > 0) {
    Char = mHexToStr[*Address >> 4];
    if ((Char >= 'A') && (Char <= 'F')) {
      Char = Char - 'A' + 'a';
    }
 
    *OutBufPtr++ = Char;
 
    Char = mHexToStr[*Address & 0x0f];
    if ((Char >= 'A') && (Char <= 'F')) {
      Char = Char - 'A' + 'a';
    }
 
    *OutBufPtr++ = Char;
 
    Address++;
    Length--;
  }
 
  *OutBufPtr = '\0';   // the end of the buffer
  SendPacket (OutBuffer);
}
 
UINTN
SendPacket (
  IN  CHAR8  *PacketData
  )
{
  UINT8  CheckSum;
  UINTN  Timeout;
  CHAR8  *Ptr;
  CHAR8  TestChar;
  UINTN  Count;
 
  Timeout = PcdGet32 (PcdGdbMaxPacketRetryCount);
 
  Count = 0;
  do {
    Ptr = PacketData;
 
    if (Timeout-- == 0) {
      // Only try a finite number of times so we don't get stuck in the loop
      return Count;
    }
 
    // Packet prefix
    GdbPutChar ('$');
 
    for (CheckSum = 0, Count = 0; *Ptr != '\0'; Ptr++, Count++) {
      GdbPutChar (*Ptr);
      CheckSum = CheckSum + *Ptr;
    }
 
    // Packet terminating character and checksum
    GdbPutChar ('#');
    GdbPutChar (mHexToStr[CheckSum >> 4]);
    GdbPutChar (mHexToStr[CheckSum & 0x0F]);
 
    TestChar =  GdbGetChar ();
  } while (TestChar != '+');
 
  return Count;
}
 
UINTN
ReceivePacket (
  OUT  CHAR8  *PacketData,
  IN   UINTN  PacketDataSize
  )
{
  UINT8  CheckSum;
  UINTN  Index;
  CHAR8  Char;
  CHAR8  SumString[3];
  CHAR8  TestChar;
 
  ZeroMem (PacketData, PacketDataSize);
 
  for ( ; ;) {
    // wait for the start of a packet
    TestChar = GdbGetChar ();
    while (TestChar != '$') {
      TestChar = GdbGetChar ();
    }
 
retry:
    for (Index = 0, CheckSum = 0; Index < (PacketDataSize - 1); Index++) {
      Char = GdbGetChar ();
      if (Char == '$') {
        goto retry;
      }
 
      if (Char == '#') {
        break;
      }
 
      PacketData[Index] = Char;
      CheckSum          = CheckSum + Char;
    }
 
    PacketData[Index] = '\0';
 
    if (Index == PacketDataSize) {
      continue;
    }
 
    SumString[0] = GdbGetChar ();
    SumString[1] = GdbGetChar ();
    SumString[2] = '\0';
 
    if (AsciiStrHexToUintn (SumString) == CheckSum) {
      // Ack: Success
      GdbPutChar ('+');
 
      // Null terminate the callers string
      PacketData[Index] = '\0';
      return Index;
    } else {
      // Ack: Failure
      GdbPutChar ('-');
    }
  }
 
  // return 0;
}
 
VOID
EmptyBuffer (
  IN  CHAR8  *Buf
  )
{
  *Buf = '\0';
}
 
INTN
HexCharToInt (
  IN  CHAR8  Char
  )
{
  if ((Char >= 'A') && (Char <= 'F')) {
    return Char - 'A' + 10;
  } else if ((Char >= 'a') && (Char <= 'f')) {
    return Char - 'a' + 10;
  } else if ((Char >= '0') && (Char <= '9')) {
    return Char - '0';
  } else {
    // if not a hex value, return a negative value
    return -1;
  }
}
 
// 'E' + the biggest error number is 255, so its 2 hex digits + buffer end
CHAR8  *gError = "E__";
 
VOID
EFIAPI
SendError (
  IN  UINT8  ErrorNum
  )
{
  //
  // Replace _, or old data, with current errno
  //
  gError[1] = mHexToStr[ErrorNum >> 4];
  gError[2] = mHexToStr[ErrorNum & 0x0f];
 
  SendPacket (gError); // send buffer
}
 
VOID
EFIAPI
SendSuccess (
  VOID
  )
{
  SendPacket ("OK"); // send buffer
}
 
VOID
EFIAPI
SendNotSupported (
  VOID
  )
{
  SendPacket ("");
}
 
VOID
GdbSendTSignal (
  IN  EFI_SYSTEM_CONTEXT  SystemContext,
  IN  UINT8               GdbExceptionType
  )
{
  CHAR8       TSignalBuffer[128];
  CHAR8       *TSignalPtr;
  UINTN       BreakpointDetected;
  BREAK_TYPE  BreakType;
  UINTN       DataAddress;
  CHAR8       *WatchStrPtr = NULL;
  UINTN       RegSize;
 
  TSignalPtr = &TSignalBuffer[0];
 
  // Construct TSignal packet
  *TSignalPtr++ = 'T';
 
  //
  // replace _, or previous value, with Exception type
  //
  *TSignalPtr++ = mHexToStr[GdbExceptionType >> 4];
  *TSignalPtr++ = mHexToStr[GdbExceptionType & 0x0f];
 
  if (GdbExceptionType == GDB_SIGTRAP) {
    if (gSymbolTableUpdate) {
      //
      // We can only send back on reason code. So if the flag is set it means the breakpoint is from our event handler
      //
      WatchStrPtr = "library:;";
      while (*WatchStrPtr != '\0') {
        *TSignalPtr++ = *WatchStrPtr++;
      }
 
      gSymbolTableUpdate = FALSE;
    } else {
      //
      // possible n:r pairs
      //
 
      // Retrieve the breakpoint number
      BreakpointDetected = GetBreakpointDetected (SystemContext);
 
      // Figure out if the exception is happend due to watch, rwatch or awatch.
      BreakType = GetBreakpointType (SystemContext, BreakpointDetected);
 
      // INFO: rwatch is not supported due to the way IA32 debug registers work
      if ((BreakType == DataWrite) || (BreakType == DataRead) || (BreakType == DataReadWrite)) {
        // Construct n:r pair
        DataAddress = GetBreakpointDataAddress (SystemContext, BreakpointDetected);
 
        // Assign appropriate buffer to print particular watchpoint type
        if (BreakType == DataWrite) {
          WatchStrPtr = "watch";
        } else if (BreakType == DataRead) {
          WatchStrPtr = "rwatch";
        } else if (BreakType == DataReadWrite) {
          WatchStrPtr = "awatch";
        }
 
        while (*WatchStrPtr != '\0') {
          *TSignalPtr++ = *WatchStrPtr++;
        }
 
        *TSignalPtr++ = ':';
 
        // Set up series of bytes in big-endian byte order. "awatch" won't work with little-endian byte order.
        RegSize = REG_SIZE;
        while (RegSize > 0) {
          RegSize       = RegSize-4;
          *TSignalPtr++ = mHexToStr[(UINT8)(DataAddress >> RegSize) & 0xf];
        }
 
        // Always end n:r pair with ';'
        *TSignalPtr++ = ';';
      }
    }
  }
 
  *TSignalPtr = '\0';
 
  SendPacket (TSignalBuffer);
}
 
UINT8
ConvertEFItoGDBtype (
  IN  EFI_EXCEPTION_TYPE  EFIExceptionType
  )
{
  UINTN  Index;
 
  for (Index = 0; Index < MaxEfiException (); Index++) {
    if (gExceptionType[Index].Exception == EFIExceptionType) {
      return gExceptionType[Index].SignalNo;
    }
  }
 
  return GDB_SIGTRAP; // this is a GDB trap
}
 
VOID
EFIAPI
ReadFromMemory (
  CHAR8  *PacketData
  )
{
  UINTN  Address;
  UINTN  Length;
  CHAR8  AddressBuffer[MAX_ADDR_SIZE]; // the buffer that will hold the address in hex chars
  CHAR8  *AddrBufPtr;                  // pointer to the address buffer
  CHAR8  *InBufPtr;                    
 
  AddrBufPtr = AddressBuffer;
  InBufPtr   = &PacketData[1];
  while (*InBufPtr != ',') {
    *AddrBufPtr++ = *InBufPtr++;
  }
 
  *AddrBufPtr = '\0';
 
  InBufPtr++; // this skips ',' in the buffer
 
  /* Error checking */
  if (AsciiStrLen (AddressBuffer) >= MAX_ADDR_SIZE) {
    Print ((CHAR16 *)L"Address is too long\n");
    SendError (GDB_EBADMEMADDRBUFSIZE);
    return;
  }
 
  // 2 = 'm' + ','
  if (AsciiStrLen (PacketData) - AsciiStrLen (AddressBuffer) - 2 >= MAX_LENGTH_SIZE) {
    Print ((CHAR16 *)L"Length is too long\n");
    SendError (GDB_EBADMEMLENGTH);
    return;
  }
 
  Address = AsciiStrHexToUintn (AddressBuffer);
  Length  = AsciiStrHexToUintn (InBufPtr);
 
  TransferFromMemToOutBufAndSend (Length, (unsigned char *)Address);
}
 
VOID
EFIAPI
WriteToMemory (
  IN CHAR8  *PacketData
  )
{
  UINTN  Address;
  UINTN  Length;
  UINTN  MessageLength;
  CHAR8  AddressBuffer[MAX_ADDR_SIZE];  // the buffer that will hold the Address in hex chars
  CHAR8  LengthBuffer[MAX_LENGTH_SIZE]; // the buffer that will hold the Length in hex chars
  CHAR8  *AddrBufPtr;                   // pointer to the Address buffer
  CHAR8  *LengthBufPtr;                 // pointer to the Length buffer
  CHAR8  *InBufPtr;                     
 
  AddrBufPtr   = AddressBuffer;
  LengthBufPtr = LengthBuffer;
  InBufPtr     = &PacketData[1];
 
  while (*InBufPtr != ',') {
    *AddrBufPtr++ = *InBufPtr++;
  }
 
  *AddrBufPtr = '\0';
 
  InBufPtr++; // this skips ',' in the buffer
 
  while (*InBufPtr != ':') {
    *LengthBufPtr++ = *InBufPtr++;
  }
 
  *LengthBufPtr = '\0';
 
  InBufPtr++; // this skips ':' in the buffer
 
  Address = AsciiStrHexToUintn (AddressBuffer);
  Length  = AsciiStrHexToUintn (LengthBuffer);
 
  /* Error checking */
 
  // Check if Address is not too long.
  if (AsciiStrLen (AddressBuffer) >= MAX_ADDR_SIZE) {
    Print ((CHAR16 *)L"Address too long..\n");
    SendError (GDB_EBADMEMADDRBUFSIZE);
    return;
  }
 
  // Check if message length is not too long
  if (AsciiStrLen (LengthBuffer) >= MAX_LENGTH_SIZE) {
    Print ((CHAR16 *)L"Length too long..\n");
    SendError (GDB_EBADMEMLENGBUFSIZE);
    return;
  }
 
  // Check if Message is not too long/short.
  // 3 = 'M' + ',' + ':'
  MessageLength = (AsciiStrLen (PacketData) - AsciiStrLen (AddressBuffer) - AsciiStrLen (LengthBuffer) - 3);
  if (MessageLength != (2*Length)) {
    // Message too long/short. New data is not the right size.
    SendError (GDB_EBADMEMDATASIZE);
    return;
  }
 
  TransferFromInBufToMem (Length, (unsigned char *)Address, InBufPtr);
}
 
UINTN
ParseBreakpointPacket (
  IN  CHAR8  *PacketData,
  OUT UINTN  *Type,
  OUT UINTN  *Address,
  OUT UINTN  *Length
  )
{
  CHAR8  AddressBuffer[MAX_ADDR_SIZE];
  CHAR8  *AddressBufferPtr;
  CHAR8  *PacketDataPtr;
 
  PacketDataPtr    = &PacketData[1];
  AddressBufferPtr = AddressBuffer;
 
  *Type = AsciiStrHexToUintn (PacketDataPtr);
 
  // Breakpoint/watchpoint type should be between 0 to 4
  if (*Type > 4) {
    Print ((CHAR16 *)L"Type is invalid\n");
    return 22; // EINVAL: Invalid argument.
  }
 
  // Skip ',' in the buffer.
  while (*PacketDataPtr++ != ',') {
  }
 
  // Parse Address information
  while (*PacketDataPtr != ',') {
    *AddressBufferPtr++ = *PacketDataPtr++;
  }
 
  *AddressBufferPtr = '\0';
 
  // Check if Address is not too long.
  if (AsciiStrLen (AddressBuffer) >= MAX_ADDR_SIZE) {
    Print ((CHAR16 *)L"Address too long..\n");
    return 40; // EMSGSIZE: Message size too long.
  }
 
  *Address = AsciiStrHexToUintn (AddressBuffer);
 
  PacketDataPtr++; // This skips , in the buffer
 
  // Parse Length information
  *Length = AsciiStrHexToUintn (PacketDataPtr);
 
  // Length should be 1, 2 or 4 bytes
  if (*Length > 4) {
    Print ((CHAR16 *)L"Length is invalid\n");
    return 22; // EINVAL: Invalid argument
  }
 
  return 0; // 0 = No error
}
 
UINTN
gXferObjectReadResponse (
  IN  CHAR8  Type,
  IN  CHAR8  *Str
  )
{
  CHAR8  *OutBufPtr;              // pointer to the output buffer
  CHAR8  Char;
  UINTN  Count;
 
  // Response starts with 'm' or 'l' if it is the end
  OutBufPtr    = gOutBuffer;
  *OutBufPtr++ = Type;
  Count        = 1;
 
  // Binary data encoding
  OutBufPtr = gOutBuffer;
  while (*Str != '\0') {
    Char = *Str++;
    if ((Char == 0x7d) || (Char == 0x23) || (Char == 0x24) || (Char == 0x2a)) {
      // escape character
      *OutBufPtr++ = 0x7d;
 
      Char ^= 0x20;
    }
 
    *OutBufPtr++ = Char;
    Count++;
  }
 
  *OutBufPtr = '\0';   // the end of the buffer
  SendPacket (gOutBuffer);
 
  return Count;
}
 
VOID *
EFIAPI
PeCoffLoaderGetDebuggerInfo (
  IN VOID   *Pe32Data,
  OUT VOID  **DebugBase
  )
{
  EFI_IMAGE_DOS_HEADER                 *DosHdr;
  EFI_IMAGE_OPTIONAL_HEADER_PTR_UNION  Hdr;
  EFI_IMAGE_DATA_DIRECTORY             *DirectoryEntry;
  EFI_IMAGE_DEBUG_DIRECTORY_ENTRY      *DebugEntry;
  UINTN                                DirCount;
  VOID                                 *CodeViewEntryPointer;
  INTN                                 TEImageAdjust;
  UINT32                               NumberOfRvaAndSizes;
  UINT16                               Magic;
  UINTN                                SizeOfHeaders;
 
  ASSERT (Pe32Data   != NULL);
 
  TEImageAdjust       = 0;
  DirectoryEntry      = NULL;
  DebugEntry          = NULL;
  NumberOfRvaAndSizes = 0;
  SizeOfHeaders       = 0;
 
  DosHdr = (EFI_IMAGE_DOS_HEADER *)Pe32Data;
  if (DosHdr->e_magic == EFI_IMAGE_DOS_SIGNATURE) {
    //
    // DOS image header is present, so read the PE header after the DOS image header.
    //
    Hdr.Pe32 = (EFI_IMAGE_NT_HEADERS32 *)((UINTN)Pe32Data + (UINTN)((DosHdr->e_lfanew) & 0x0ffff));
  } else {
    //
    // DOS image header is not present, so PE header is at the image base.
    //
    Hdr.Pe32 = (EFI_IMAGE_NT_HEADERS32 *)Pe32Data;
  }
 
  if (Hdr.Te->Signature == EFI_TE_IMAGE_HEADER_SIGNATURE) {
    if (Hdr.Te->DataDirectory[EFI_TE_IMAGE_DIRECTORY_ENTRY_DEBUG].VirtualAddress != 0) {
      DirectoryEntry = &Hdr.Te->DataDirectory[EFI_TE_IMAGE_DIRECTORY_ENTRY_DEBUG];
      TEImageAdjust  = sizeof (EFI_TE_IMAGE_HEADER) - Hdr.Te->StrippedSize;
      DebugEntry     = (EFI_IMAGE_DEBUG_DIRECTORY_ENTRY *)((UINTN)Hdr.Te +
                                                           Hdr.Te->DataDirectory[EFI_TE_IMAGE_DIRECTORY_ENTRY_DEBUG].VirtualAddress +
                                                           TEImageAdjust);
    }
 
    SizeOfHeaders = sizeof (EFI_TE_IMAGE_HEADER) + (UINTN)Hdr.Te->BaseOfCode - (UINTN)Hdr.Te->StrippedSize;
 
    // __APPLE__ check this math...
    *DebugBase = ((CHAR8 *)Pe32Data) -  TEImageAdjust;
  } else if (Hdr.Pe32->Signature == EFI_IMAGE_NT_SIGNATURE) {
    *DebugBase = Pe32Data;
 
    //
    // NOTE: We use Machine field to identify PE32/PE32+, instead of Magic.
    //       It is due to backward-compatibility, for some system might
    //       generate PE32+ image with PE32 Magic.
    //
    switch (Hdr.Pe32->FileHeader.Machine) {
      case EFI_IMAGE_MACHINE_IA32:
        //
        // Assume PE32 image with IA32 Machine field.
        //
        Magic = EFI_IMAGE_NT_OPTIONAL_HDR32_MAGIC;
        break;
      case EFI_IMAGE_MACHINE_X64:
      case EFI_IMAGE_MACHINE_IA64:
        //
        // Assume PE32+ image with X64 or IPF Machine field
        //
        Magic = EFI_IMAGE_NT_OPTIONAL_HDR64_MAGIC;
        break;
      default:
        //
        // For unknown Machine field, use Magic in optional Header
        //
        Magic = Hdr.Pe32->OptionalHeader.Magic;
    }
 
    if (Magic == EFI_IMAGE_NT_OPTIONAL_HDR32_MAGIC) {
      //
      // Use PE32 offset get Debug Directory Entry
      //
      SizeOfHeaders       = Hdr.Pe32->OptionalHeader.SizeOfHeaders;
      NumberOfRvaAndSizes = Hdr.Pe32->OptionalHeader.NumberOfRvaAndSizes;
      DirectoryEntry      = (EFI_IMAGE_DATA_DIRECTORY *)&(Hdr.Pe32->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_DEBUG]);
      DebugEntry          = (EFI_IMAGE_DEBUG_DIRECTORY_ENTRY *)((UINTN)Pe32Data + DirectoryEntry->VirtualAddress);
    } else if (Hdr.Pe32->OptionalHeader.Magic == EFI_IMAGE_NT_OPTIONAL_HDR64_MAGIC) {
      //
      // Use PE32+ offset get Debug Directory Entry
      //
      SizeOfHeaders       = Hdr.Pe32Plus->OptionalHeader.SizeOfHeaders;
      NumberOfRvaAndSizes = Hdr.Pe32Plus->OptionalHeader.NumberOfRvaAndSizes;
      DirectoryEntry      = (EFI_IMAGE_DATA_DIRECTORY *)&(Hdr.Pe32Plus->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_DEBUG]);
      DebugEntry          = (EFI_IMAGE_DEBUG_DIRECTORY_ENTRY *)((UINTN)Pe32Data + DirectoryEntry->VirtualAddress);
    }
 
    if (NumberOfRvaAndSizes <= EFI_IMAGE_DIRECTORY_ENTRY_DEBUG) {
      DirectoryEntry = NULL;
      DebugEntry     = NULL;
    }
  } else {
    return NULL;
  }
 
  if ((DebugEntry == NULL) || (DirectoryEntry == NULL)) {
    return NULL;
  }
 
  for (DirCount = 0; DirCount < DirectoryEntry->Size; DirCount += sizeof (EFI_IMAGE_DEBUG_DIRECTORY_ENTRY), DebugEntry++) {
    if (DebugEntry->Type == EFI_IMAGE_DEBUG_TYPE_CODEVIEW) {
      if (DebugEntry->SizeOfData > 0) {
        CodeViewEntryPointer = (VOID *)((UINTN)DebugEntry->RVA + ((UINTN)Pe32Data) + (UINTN)TEImageAdjust);
        switch (*(UINT32 *)CodeViewEntryPointer) {
          case CODEVIEW_SIGNATURE_NB10:
            return (VOID *)((CHAR8 *)CodeViewEntryPointer + sizeof (EFI_IMAGE_DEBUG_CODEVIEW_NB10_ENTRY));
          case CODEVIEW_SIGNATURE_RSDS:
            return (VOID *)((CHAR8 *)CodeViewEntryPointer + sizeof (EFI_IMAGE_DEBUG_CODEVIEW_RSDS_ENTRY));
          case CODEVIEW_SIGNATURE_MTOC:
            *DebugBase = (VOID *)(UINTN)((UINTN)DebugBase - SizeOfHeaders);
            return (VOID *)((CHAR8 *)CodeViewEntryPointer + sizeof (EFI_IMAGE_DEBUG_CODEVIEW_MTOC_ENTRY));
          default:
            break;
        }
      }
    }
  }
 
  (void)SizeOfHeaders;
  return NULL;
}
 
VOID
QxferLibrary (
  IN  UINTN  Offset,
  IN  UINTN  Length
  )
{
  VOID   *LoadAddress;
  CHAR8  *Pdb;
  UINTN  Size;
 
  if (Offset != gPacketqXferLibraryOffset) {
    SendError (GDB_EINVALIDARG);
    Print (L"\nqXferLibrary (%d, %d) != %d\n", Offset, Length, gPacketqXferLibraryOffset);
 
    // Force a retry from the beginning
    gPacketqXferLibraryOffset = 0;
 
    return;
  }
 
  if (Offset == 0) {
    gPacketqXferLibraryOffset += gXferObjectReadResponse ('m', "<library-list>\n");
 
    // The owner of the table may have had to ralloc it so grab a fresh copy every time
    // we assume qXferLibrary will get called over and over again until the entire XML table is
    // returned in a tight loop. Since we are in the debugger the table should not get updated
    gDebugTable              = gDebugImageTableHeader->EfiDebugImageInfoTable;
    gEfiDebugImageTableEntry = 0;
    return;
  }
 
  if (gDebugTable != NULL) {
    for ( ; gEfiDebugImageTableEntry < gDebugImageTableHeader->TableSize; gEfiDebugImageTableEntry++, gDebugTable++) {
      if (gDebugTable->NormalImage != NULL) {
        if ((gDebugTable->NormalImage->ImageInfoType == EFI_DEBUG_IMAGE_INFO_TYPE_NORMAL) &&
            (gDebugTable->NormalImage->LoadedImageProtocolInstance != NULL))
        {
          Pdb = PeCoffLoaderGetDebuggerInfo (
                  gDebugTable->NormalImage->LoadedImageProtocolInstance->ImageBase,
                  &LoadAddress
                  );
          if (Pdb != NULL) {
            Size = AsciiSPrint (
                     gXferLibraryBuffer,
                     sizeof (gXferLibraryBuffer),
                     "  <library name=\"%a\"><segment address=\"0x%p\"/></library>\n",
                     Pdb,
                     LoadAddress
                     );
            if ((Size != 0) && (Size != (sizeof (gXferLibraryBuffer) - 1))) {
              gPacketqXferLibraryOffset += gXferObjectReadResponse ('m', gXferLibraryBuffer);
 
              // Update loop variables so we are in the right place when we get back
              gEfiDebugImageTableEntry++;
              gDebugTable++;
              return;
            } else {
              // We could handle <library> entires larger than sizeof (gXferLibraryBuffer) here if
              // needed by breaking up into N packets
              // "<library name=\"%s
              // the rest of the string (as many packets as required
              // \"><segment address=\"%d\"/></library> (fixed size)
              //
              // But right now we just skip any entry that is too big
            }
          }
        }
      }
    }
  }
 
  gXferObjectReadResponse ('l', "</library-list>\n");
  gPacketqXferLibraryOffset = 0;
  return;
}
 
VOID
EFIAPI
GdbExceptionHandler (
  IN  EFI_EXCEPTION_TYPE     ExceptionType,
  IN OUT EFI_SYSTEM_CONTEXT  SystemContext
  )
{
  UINT8  GdbExceptionType;
  CHAR8  *Ptr;
 
  if (ValidateException (ExceptionType, SystemContext) == FALSE) {
    return;
  }
 
  RemoveSingleStep (SystemContext);
 
  GdbExceptionType = ConvertEFItoGDBtype (ExceptionType);
  GdbSendTSignal (SystemContext, GdbExceptionType);
 
  for ( ; ; ) {
    ReceivePacket (gInBuffer, MAX_BUF_SIZE);
 
    switch (gInBuffer[0]) {
      case '?':
        GdbSendTSignal (SystemContext, GdbExceptionType);
        break;
 
      case 'c':
        ContinueAtAddress (SystemContext, gInBuffer);
        return;
 
      case 'g':
        ReadGeneralRegisters (SystemContext);
        break;
 
      case 'G':
        WriteGeneralRegisters (SystemContext, gInBuffer);
        break;
 
      case 'H':
        // Return "OK" packet since we don't have more than one thread.
        SendSuccess ();
        break;
 
      case 'm':
        ReadFromMemory (gInBuffer);
        break;
 
      case 'M':
        WriteToMemory (gInBuffer);
        break;
 
      case 'P':
        WriteNthRegister (SystemContext, gInBuffer);
        break;
 
      //
      // Still debugging this code. Not used in Darwin
      //
      case 'q':
        // General Query Packets
        if (AsciiStrnCmp (gInBuffer, "qSupported", 10) == 0) {
          // return what we currently support, we don't parse what gdb supports
          AsciiSPrint (gOutBuffer, MAX_BUF_SIZE, "qXfer:libraries:read+;PacketSize=%d", MAX_BUF_SIZE);
          SendPacket (gOutBuffer);
        } else if (AsciiStrnCmp (gInBuffer, "qXfer:libraries:read::", 22) == 0) {
          // ‘qXfer:libraries:read::offset,length
          // gInBuffer[22] is offset string, ++Ptr is length string’
          for (Ptr = &gInBuffer[22]; *Ptr != ','; Ptr++) {
          }
 
          // Not sure if multi-radix support is required. Currently only support decimal
          QxferLibrary (AsciiStrHexToUintn (&gInBuffer[22]), AsciiStrHexToUintn (++Ptr));
        }
 
        if (AsciiStrnCmp (gInBuffer, "qOffsets", 10) == 0) {
          AsciiSPrint (gOutBuffer, MAX_BUF_SIZE, "Text=1000;Data=f000;Bss=f000");
          SendPacket (gOutBuffer);
        } else {
          // Send empty packet
          SendNotSupported ();
        }
 
        break;
 
      case 's':
        SingleStep (SystemContext, gInBuffer);
        return;
 
      case 'z':
        RemoveBreakPoint (SystemContext, gInBuffer);
        break;
 
      case 'Z':
        InsertBreakPoint (SystemContext, gInBuffer);
        break;
 
      default:
        // Send empty packet
        SendNotSupported ();
        break;
    }
  }
}
 
VOID
EFIAPI
GdbPeriodicCallBack (
  IN OUT EFI_SYSTEM_CONTEXT  SystemContext
  )
{
  //
  // gCtrlCBreakFlag may have been set from a previous F response package
  // and we set the global as we need to process it at a point where we
  // can update the system context. If we are in the middle of processing
  // a F Packet it is not safe to read the GDB serial stream so we need
  // to skip it on this check
  //
  if (!gCtrlCBreakFlag && !gProcessingFPacket) {
    //
    // Ctrl-C was not pending so grab any pending characters and see if they
    // are a Ctrl-c (0x03). If so set the Ctrl-C global.
    //
    while (TRUE) {
      if (!GdbIsCharAvailable ()) {
        //
        // No characters are pending so exit the loop
        //
        break;
      }
 
      if (GdbGetChar () == 0x03) {
        gCtrlCBreakFlag = TRUE;
        //
        // We have a ctrl-c so exit the loop
        //
        break;
      }
    }
  }
 
  if (gCtrlCBreakFlag) {
    //
    // Update the context to force a single step trap when we exit the GDB
    // stub. This will transfer control to GdbExceptionHandler () and let
    // us break into the program. We don't want to break into the GDB stub.
    //
    AddSingleStep (SystemContext);
    gCtrlCBreakFlag = FALSE;
  }
}