/** @file
  IPF specific functions to support Debug Support protocol.

Copyright (c) 2006 - 2008, 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.             

**/

#include "PlDebugSupport.h"

BOOLEAN  mInHandler = FALSE;

//
// 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;

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;


/**
  IPF specific DebugSupport driver initialization. 

  Must be public because it's referenced from DebugSupport.c

  @retval  EFI_SUCCESS     Always.

**/
EFI_STATUS
PlInitializeDebugSupportDriver (
  VOID
  )
{
  ZeroMem (IvtEntryTable, sizeof (IvtEntryTable));
  ExternalInterruptCount = 0;
  return EFI_SUCCESS;
}

/**
  Unload handler that is called during UnloadImage() - deallocates pool memory
  used by the driver. 

  Must be public because it's referenced from DebugSuport.c

  @param  ImageHandle    The firmware allocated handle for the EFI image.

  @retval EFI_SUCCESS    Always.

**/
EFI_STATUS
EFIAPI
PlUnloadDebugSupportDriver (
  IN EFI_HANDLE       ImageHandle
  )
{
  EFI_EXCEPTION_TYPE  ExceptionType;

  for (ExceptionType = 0; ExceptionType < NUM_IVT_ENTRIES; ExceptionType++) {
    ManageIvtEntryTable (ExceptionType, NULL, NULL);
  }

  return EFI_SUCCESS;
}

/**
  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.

  @param  ExceptionType        Specifies which processor exception.
  @param  Context              System Context.
**/
VOID
CommonHandler (
  IN EFI_EXCEPTION_TYPE ExceptionType,
  IN EFI_SYSTEM_CONTEXT Context
  )
{
  DEBUG_CODE_BEGIN ();
    if (mInHandler) {
      DEBUG ((EFI_D_INFO, "ERROR: Re-entered debugger!\n"
                                    "       ExceptionType == %X\n"
                                    "       Context       == %X\n"
                                    "       Context.SystemContextIpf->CrIip  == %LX\n"
                                    "       Context.SystemContextIpf->CrIpsr == %LX\n"
                                    "       mInHandler     == %X\n",
                                    (INT32)ExceptionType, 
                                    Context, 
                                    Context.SystemContextIpf->CrIip,
                                    Context.SystemContextIpf->CrIpsr,
                                    mInHandler));
    }
  DEBUG_CODE_END ();

  ASSERT (!mInHandler);
  mInHandler = 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);
  }

  mInHandler = FALSE;
}

/**
  Given an integer number, return the physical address of the entry point in the IFT.

  @param  HandlerIndex       Index of the Handler 
  @param  EntryPoint         IFT Entrypoint

**/
VOID
GetHandlerEntryPoint (
  UINTN   HandlerIndex,
  VOID    **EntryPoint
  )
{
  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;
}

/**
  This is the worker function that uninstalls and removes all handlers.

  @param  ExceptionType     Specifies which processor exception.
  @param  NewBundles        New Boundles.
  @param  NewCallback       A pointer to the new function to be registered.

  @retval EFI_ALEADY_STARTED Ivt already hooked.
  @retval EFI_SUCCESS        Successfully uninstalled.

**/
EFI_STATUS
ManageIvtEntryTable (
  IN  EFI_EXCEPTION_TYPE           ExceptionType,
  IN  BUNDLE                       NewBundles[NUM_BUNDLES_IN_STUB],
  IN  VOID                         (*NewCallback) ()
  )
{
  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
      //
      ZeroMem (&IvtEntryTable[ExceptionType], sizeof (IVT_ENTRY));
    }
  } 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;
}

/**
  Saves original IVT contents and inserts a few new bundles which are fixed up
  to store the ExceptionType and then call the common handler.

  @param  ExceptionType      Specifies which processor exception.
  @param  NewBundles         New Boundles.
  @param  NewCallback        A pointer to the new function to be hooked.

**/
VOID
HookEntry (
  IN  EFI_EXCEPTION_TYPE  ExceptionType,
  IN  BUNDLE              NewBundles[4],
  IN  VOID                (*NewCallback) ()
  )
{
  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;
}

/**
  Restores original IVT contents when unregistering a callback function.

  @param  ExceptionType     Specifies which processor exception.

**/
VOID
UnhookEntry (
  IN  EFI_EXCEPTION_TYPE  ExceptionType
  )
{
  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);
}

/**
  Sets up cache flush and calls assembly function to chain external interrupt.

  Records new callback in IvtEntryTable.

  @param  NewCallback     A pointer to the interrupt handle.

**/
VOID
ChainExternalInterrupt (
  IN  VOID  (*NewCallback) ()
  )
{
  VOID  *Start;

  Start = (VOID *) ((UINT8 *) GetIva () + 0x400 * EXCEPT_IPF_EXTERNAL_INTERRUPT + 0x400);
  IvtEntryTable[EXCEPT_IPF_EXTERNAL_INTERRUPT].RegisteredCallback = NewCallback;
  ChainHandler ();
  InstructionCacheFlush (Start, 0x400);
}

/**
  Sets up cache flush and calls assembly function to restore external interrupt.
  Removes registered callback from IvtEntryTable.

**/
VOID
UnchainExternalInterrupt (
  VOID
  )
{
  VOID  *Start;

  Start = (VOID *) ((UINT8 *) GetIva () + 0x400 * EXCEPT_IPF_EXTERNAL_INTERRUPT + 0x400);
  UnchainHandler ();
  InstructionCacheFlush (Start, 0x400);
  IvtEntryTable[EXCEPT_IPF_EXTERNAL_INTERRUPT].RegisteredCallback = NULL;
}

/**
  Returns the maximum value that may be used for the ProcessorIndex parameter in
  RegisterPeriodicCallback() and RegisterExceptionCallback().                   
    
  Hard coded to support only 1 processor for now.

  @param  This                  A pointer to the EFI_DEBUG_SUPPORT_PROTOCOL instance.
  @param  MaxProcessorIndex     Pointer to a caller-allocated UINTN in which the maximum supported
                                processor index is returned. Always 0 returned.                                     
                                
  @retval EFI_SUCCESS           Always returned with **MaxProcessorIndex set to 0.

**/
EFI_STATUS
EFIAPI
GetMaximumProcessorIndex (
  IN EFI_DEBUG_SUPPORT_PROTOCOL    *This,
  OUT UINTN                        *MaxProcessorIndex
  )
{
  *MaxProcessorIndex = 0;
  return (EFI_SUCCESS);
}

/**
  Registers a function to be called back periodically in interrupt context.
    
  @param  This                  A pointer to the EFI_DEBUG_SUPPORT_PROTOCOL instance.
  @param  ProcessorIndex        Specifies which processor the callback function applies to.
  @param  PeriodicCallback      A pointer to a function of type PERIODIC_CALLBACK that is the main
                                periodic entry point of the debug agent.
                                
  @retval EFI_SUCCESS           The function completed successfully.  
  @retval EFI_ALREADY_STARTED   Non-NULL PeriodicCallback parameter when a callback
                                function was previously registered.                
  @retval EFI_OUT_OF_RESOURCES  System has insufficient memory resources to register new callback                               
                                function. 
**/
EFI_STATUS
EFIAPI
RegisterPeriodicCallback (
  IN EFI_DEBUG_SUPPORT_PROTOCOL     *This,
  IN UINTN                          ProcessorIndex,
  IN EFI_PERIODIC_CALLBACK          PeriodicCallback
  )
{
  return ManageIvtEntryTable (EXCEPT_IPF_EXTERNAL_INTERRUPT, NULL, PeriodicCallback);
}

/**
  Registers a function to be called when a given processor exception occurs.

  This code executes in boot services context.
    
  @param  This                  A pointer to the EFI_DEBUG_SUPPORT_PROTOCOL instance.
  @param  ProcessorIndex        Specifies which processor the callback function applies to.
  @param  ExceptionCallback     A pointer to a function of type EXCEPTION_CALLBACK that is called
                                when the processor exception specified by ExceptionType occurs.  
  @param  ExceptionType         Specifies which processor exception to hook.                       
                                
  @retval EFI_SUCCESS           The function completed successfully.  
  @retval EFI_ALREADY_STARTED   Non-NULL PeriodicCallback parameter when a callback
                                function was previously registered.                
  @retval EFI_OUT_OF_RESOURCES  System has insufficient memory resources to register new callback                               
                                function.
**/
EFI_STATUS
EFIAPI
RegisterExceptionCallback (
  IN EFI_DEBUG_SUPPORT_PROTOCOL    *This,
  IN UINTN                         ProcessorIndex,
  IN EFI_EXCEPTION_CALLBACK        NewCallback,
  IN EFI_EXCEPTION_TYPE            ExceptionType
  )
{
  return ManageIvtEntryTable (
          ExceptionType,
          (BUNDLE *) ((EFI_PLABEL *) HookStub)->EntryPoint,
          NewCallback
          );
}

/**
  Invalidates processor instruction cache for a memory range. Subsequent execution in this range
  causes a fresh memory fetch to retrieve code to be executed.                                  
    
  @param  This                  A pointer to the EFI_DEBUG_SUPPORT_PROTOCOL instance.
  @param  ProcessorIndex        Specifies which processor's instruction cache is to be invalidated.
  @param  Start                 Specifies the physical base of the memory range to be invalidated.                                
  @param  Length                Specifies the minimum number of bytes in the processor's instruction
                                cache to invalidate.                                                 
                                
  @retval EFI_SUCCESS           Always returned.

**/
EFI_STATUS
EFIAPI
InvalidateInstructionCache (
  IN EFI_DEBUG_SUPPORT_PROTOCOL    *This,
  IN UINTN                         ProcessorIndex,
  IN VOID                          *Start,
  IN UINTN                         Length
  )
{
  InstructionCacheFlush (Start, Length);
  return EFI_SUCCESS;
}