/**@file
  IPF specific debug support functions

Copyright (c) 2006, Intel Corporation                                                         
All rights reserved. This program and the accompanying materials                          
are licensed and made available under the terms and conditions of the BSD License         
which accompanies this distribution.  The full text of the license may be found at        
http://opensource.org/licenses/bsd-license.php                                            
                                                                                          
THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,                     
WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.             

**/

//
// private header files
//
#include "plDebugSupport.h"

typedef struct {
  UINT64  low;
  UINT64  high;
} BUNDLE;

//
// number of bundles to swap in ivt
//
#define NUM_BUNDLES_IN_STUB 5
#define NUM_IVT_ENTRIES     64

typedef struct {
  BUNDLE  OrigBundles[NUM_BUNDLES_IN_STUB];
  VOID (*RegisteredCallback) ();
} IVT_ENTRY;

STATIC
EFI_STATUS
ManageIvtEntryTable (
  IN  EFI_EXCEPTION_TYPE                ExceptionType,
  IN  BUNDLE                NewBundles[4],
  IN  VOID                  (*NewCallback) ()
  );

STATIC
VOID
HookEntry (
  IN  EFI_EXCEPTION_TYPE                ExceptionType,
  IN  BUNDLE                NewBundles[4],
  IN  VOID                  (*NewCallback) ()
  );

STATIC
VOID
UnhookEntry (
  IN  EFI_EXCEPTION_TYPE    ExceptionType
  );

STATIC
VOID
ChainExternalInterrupt (
  IN  VOID                  (*NewCallback) ()
  );

STATIC
VOID
UnchainExternalInterrupt (
  VOID
  );

STATIC
VOID
GetHandlerEntryPoint (
  UINTN                     HandlerIndex,
  VOID                      **EntryPoint
  );

IVT_ENTRY IvtEntryTable[NUM_IVT_ENTRIES];

//
// IPF context record is overallocated by 512 bytes to guarantee a 512 byte alignment exists
// within the buffer and still have a large enough buffer to hold a whole IPF context record.
//
UINT8     IpfContextBuf[sizeof (EFI_SYSTEM_CONTEXT_IPF) + 512];

//
// The PatchSaveBuffer is used to store the original bundles from the IVT where it is patched
// with the common handler.
//
UINT8     PatchSaveBuffer[0x400];
UINTN     ExternalInterruptCount;

EFI_STATUS
plInitializeDebugSupportDriver (
  VOID
  )
/*++

Routine Description:
  IPF specific DebugSupport driver initialization.  Must be public because it's
  referenced from DebugSupport.c

Arguments:

Returns:

  EFI_SUCCESS

--*/
{
  SetMem (IvtEntryTable, sizeof (IvtEntryTable), 0);
  ExternalInterruptCount = 0;
  return EFI_SUCCESS;
}

EFI_STATUS
EFIAPI
plUnloadDebugSupportDriver (
  IN EFI_HANDLE       ImageHandle
  )
/*++

Routine Description:
  Unload handler that is called during UnloadImage() - deallocates pool memory
  used by the driver.  Must be public because it's referenced from DebugSuport.c

Arguments:
  ImageHandle - Image handle

Returns:

  EFI_STATUS - anything other than EFI_SUCCESS indicates the callback was not registered.

--*/
{
  EFI_EXCEPTION_TYPE  ExceptionType;

  for (ExceptionType = 0; ExceptionType < NUM_IVT_ENTRIES; ExceptionType++) {
    ManageIvtEntryTable (ExceptionType, NULL, NULL);
  }

  return EFI_SUCCESS;
}

VOID
CommonHandler (
  IN EFI_EXCEPTION_TYPE ExceptionType,
  IN EFI_SYSTEM_CONTEXT Context
  )
/*++

Routine Description:
  C routine that is called for all registered exceptions.  This is the main
  exception dispatcher.  Must be public because it's referenced from AsmFuncs.s.

Arguments:
  ExceptionType - Exception Type
  Context       - System Context

Returns:

  Nothing
  
--*/
{
  static BOOLEAN  InHandler = FALSE;

  DEBUG_CODE_BEGIN ();
    if (InHandler) {
      DEBUG ((EFI_D_INFO, "ERROR: Re-entered debugger!\n"
                                    "       ExceptionType == %X\n"
                                    "       Context       == %X\n"
                                    "       Context.SystemContextIpf->CrIip  == %X\n"
                                    "       Context.SystemContextIpf->CrIpsr == %X\n"
                                    "       InHandler     == %X\n",
                                    ExceptionType, 
                                    Context, 
                                    Context.SystemContextIpf->CrIip,
                                    Context.SystemContextIpf->CrIpsr,
                                    InHandler));
    }
  DEBUG_CODE_END ();

  ASSERT (!InHandler);
  InHandler = TRUE;
  if (IvtEntryTable[ExceptionType].RegisteredCallback != NULL) {
    if (ExceptionType != EXCEPT_IPF_EXTERNAL_INTERRUPT) {
      IvtEntryTable[ExceptionType].RegisteredCallback (ExceptionType, Context.SystemContextIpf);
    } else {
      IvtEntryTable[ExceptionType].RegisteredCallback (Context.SystemContextIpf);
    }
  } else {
    ASSERT (0);
  }

  InHandler = FALSE;
}

STATIC
VOID
GetHandlerEntryPoint (
  UINTN   HandlerIndex,
  VOID    **EntryPoint
  )
/*++

Routine Description:
  Given an integer number, return the physical address of the entry point in the IFT
  
Arguments:
  HandlerIndex - Index of the Handler 
  EntryPoint   - IFT Entrypoint

Returns:

  Nothing
  
--*/
{
  UINT8 *TempPtr;

  //
  // get base address of IVT
  //
  TempPtr = GetIva ();

  if (HandlerIndex < 20) {
    //
    // first 20 provide 64 bundles per vector
    //
    TempPtr += 0x400 * HandlerIndex;
  } else {
    //
    // the rest provide 16 bundles per vector
    //
    TempPtr += 0x5000 + 0x100 * (HandlerIndex - 20);
  }

  *EntryPoint = (VOID *) TempPtr;
}

STATIC
EFI_STATUS
ManageIvtEntryTable (
  IN  EFI_EXCEPTION_TYPE                                         ExceptionType,
  IN  BUNDLE                       NewBundles[NUM_BUNDLES_IN_STUB],
  IN  VOID                         (*NewCallback) ()
  )
/*++

Routine Description:
  This is the worker function that installs and removes all handlers
  
Arguments:
  ExceptionType  - Exception Type
  NewBundles     - New Boundles
  NewCallback    - New Callback

Returns:

  EFI_STATUS - any return other than EFI_SUCCESS indicates the request was not
  satisfied.
  EFI_ALEADY_STARTED - Ivt already hooked.
  
--*/
{
  BUNDLE  *B0Ptr;
  UINT64  InterruptFlags;
  EFI_TPL OldTpl;

  //
  // Get address of bundle 0
  //
  GetHandlerEntryPoint (ExceptionType, (VOID **) &B0Ptr);

  if (IvtEntryTable[ExceptionType].RegisteredCallback != NULL) {
    //
    // we've already installed to this vector
    //
    if (NewCallback != NULL) {
      //
      // if the input handler is non-null, error
      //
      return EFI_ALREADY_STARTED;
    } else {
      //
      // else remove the previously installed handler
      //
      OldTpl          = gBS->RaiseTPL (TPL_HIGH_LEVEL);
      InterruptFlags  = ProgramInterruptFlags (DISABLE_INTERRUPTS);
      if (ExceptionType == EXCEPT_IPF_EXTERNAL_INTERRUPT) {
        UnchainExternalInterrupt ();
      } else {
        UnhookEntry (ExceptionType);
      }

      ProgramInterruptFlags (InterruptFlags);
      gBS->RestoreTPL (OldTpl);
      //
      // re-init IvtEntryTable
      //
      SetMem (&IvtEntryTable[ExceptionType], sizeof (IVT_ENTRY), 0);
    }
  } else {
    //
    // no user handler installed on this vector
    //
    if (NewCallback != NULL) {
      OldTpl          = gBS->RaiseTPL (TPL_HIGH_LEVEL);
      InterruptFlags  = ProgramInterruptFlags (DISABLE_INTERRUPTS);
      if (ExceptionType == EXCEPT_IPF_EXTERNAL_INTERRUPT) {
        ChainExternalInterrupt (NewCallback);
      } else {
        HookEntry (ExceptionType, NewBundles, NewCallback);
      }

      ProgramInterruptFlags (InterruptFlags);
      gBS->RestoreTPL (OldTpl);
    }
  }

  return EFI_SUCCESS;
}

STATIC
VOID
HookEntry (
  IN  EFI_EXCEPTION_TYPE  ExceptionType,
  IN  BUNDLE              NewBundles[4],
  IN  VOID                (*NewCallback) ()
  )
/*++

Routine Description:
  Saves original IVT contents and inserts a few new bundles which are fixed up
  to store the ExceptionType and then call the common handler.
  
Arguments:
  ExceptionType  - Exception Type
  NewBundles     - New Boundles
  NewCallback    - New Callback

Returns:

  Nothing
    
--*/
{
  BUNDLE  *FixupBundle;
  BUNDLE  *B0Ptr;

  //
  // Get address of bundle 0
  //
  GetHandlerEntryPoint (ExceptionType, (VOID **) &B0Ptr);

  //
  // copy original bundles from IVT to IvtEntryTable so we can restore them later
  //
  CopyMem (
    IvtEntryTable[ExceptionType].OrigBundles,
    B0Ptr,
    sizeof (BUNDLE) * NUM_BUNDLES_IN_STUB
    );
  //
  // insert new B0
  //
  CopyMem (B0Ptr, NewBundles, sizeof (BUNDLE) * NUM_BUNDLES_IN_STUB);

  //
  // fixup IVT entry so it stores its index and whether or not to chain...
  //
  FixupBundle = B0Ptr + 2;
  FixupBundle->high |= ExceptionType << 36;

  InstructionCacheFlush (B0Ptr, 5);
  IvtEntryTable[ExceptionType].RegisteredCallback = NewCallback;
}

STATIC
VOID
UnhookEntry (
  IN  EFI_EXCEPTION_TYPE  ExceptionType
  )
/*++

Routine Description:
  Restores original IVT contents when unregistering a callback function
  
Arguments:
  ExceptionType  - Exception Type
  NewBundles     - New Boundles
  NewCallback    - New Callback

Returns:

  Nothing
    
--*/
{
  BUNDLE  *B0Ptr;

  //
  // Get address of bundle 0
  //
  GetHandlerEntryPoint (ExceptionType, (VOID **) &B0Ptr);
  //
  // restore original bundles in IVT
  //
  CopyMem (
    B0Ptr,
    IvtEntryTable[ExceptionType].OrigBundles,
    sizeof (BUNDLE) * NUM_BUNDLES_IN_STUB
    );
  InstructionCacheFlush (B0Ptr, 5);
}

STATIC
VOID
ChainExternalInterrupt (
  IN  VOID  (*NewCallback) ()
  )
/*++

Routine Description:
  Sets up cache flush and calls assembly function to chain external interrupt.
  Records new callback in IvtEntryTable.
  
Arguments:
  NewCallback    - New Callback

Returns:

  Nothing
    
--*/
{
  VOID  *Start;

  Start = (VOID *) ((UINT8 *) GetIva () + 0x400 * EXCEPT_IPF_EXTERNAL_INTERRUPT + 0x400);
  IvtEntryTable[EXCEPT_IPF_EXTERNAL_INTERRUPT].RegisteredCallback = NewCallback;
  ChainHandler ();
  InstructionCacheFlush (Start, 0x400);
}

STATIC
VOID
UnchainExternalInterrupt (
  VOID
  )
/*++

Routine Description:
  Sets up cache flush and calls assembly function to restore external interrupt.
  Removes registered callback from IvtEntryTable.
  
Arguments:
  Nothing
  
Returns:

  Nothing
    
--*/
{
  VOID  *Start;

  Start = (VOID *) ((UINT8 *) GetIva () + 0x400 * EXCEPT_IPF_EXTERNAL_INTERRUPT + 0x400);
  UnchainHandler ();
  InstructionCacheFlush (Start, 0x400);
  IvtEntryTable[EXCEPT_IPF_EXTERNAL_INTERRUPT].RegisteredCallback = NULL;
}

//
// The rest of the functions in this file are all member functions for the
// DebugSupport protocol
//

EFI_STATUS
EFIAPI
GetMaximumProcessorIndex (
  IN EFI_DEBUG_SUPPORT_PROTOCOL    *This,
  OUT UINTN                        *MaxProcessorIndex
  )
/*++

Routine Description: This is a DebugSupport protocol member function.  Hard
  coded to support only 1 processor for now.

Arguments:
  This              - The DebugSupport instance
  MaxProcessorIndex - The maximuim supported processor index

Returns:
  Always returns EFI_SUCCESS with *MaxProcessorIndex set to 0

--*/
{
  *MaxProcessorIndex = 0;
  return (EFI_SUCCESS);
}

EFI_STATUS
EFIAPI
RegisterPeriodicCallback (
  IN EFI_DEBUG_SUPPORT_PROTOCOL     *This,
  IN UINTN                          ProcessorIndex,
  IN EFI_PERIODIC_CALLBACK          NewPeriodicCallback
  )
/*++

Routine Description:
  DebugSupport protocol member function

Arguments:
  This             - The DebugSupport instance
  ProcessorIndex   - Which processor the callback applies to.
  PeriodicCallback - Callback function

Returns:

  EFI_STATUS - anything other than EFI_SUCCESS indicates the callback was not registered.

--*/
{
  return ManageIvtEntryTable (EXCEPT_IPF_EXTERNAL_INTERRUPT, NULL, NewPeriodicCallback);
}

EFI_STATUS
EFIAPI
RegisterExceptionCallback (
  IN EFI_DEBUG_SUPPORT_PROTOCOL    *This,
  IN UINTN                         ProcessorIndex,
  IN EFI_EXCEPTION_CALLBACK        NewCallback,
  IN EFI_EXCEPTION_TYPE            ExceptionType
  )
/*++

Routine Description:
  DebugSupport protocol member function

Arguments:
  This             - The DebugSupport instance
  ProcessorIndex   - Which processor the callback applies to.
  NewCallback      - Callback function
  ExceptionType    - Which exception to hook

Returns:

  EFI_STATUS - anything other than EFI_SUCCESS indicates the callback was not registered.

--*/
{
  return ManageIvtEntryTable (
          ExceptionType,
          (BUNDLE *) ((EFI_PLABEL *) HookStub)->EntryPoint,
          NewCallback
          );
}

EFI_STATUS
EFIAPI
InvalidateInstructionCache (
  IN EFI_DEBUG_SUPPORT_PROTOCOL    *This,
  IN UINTN                         ProcessorIndex,
  IN VOID                          *Start,
  IN UINTN                         Length
  )
/*++

Routine Description:
  DebugSupport protocol member function.  Calls assembly routine to flush cache.

Arguments:
  This             - The DebugSupport instance
  ProcessorIndex   - Which processor the callback applies to.
  Start            - Physical base of the memory range to be invalidated
  Length           - mininum number of bytes in instruction cache to invalidate

Returns:
  EFI_SUCCESS

--*/
{
  InstructionCacheFlush (Start, Length);
  return (EFI_SUCCESS);
}
