PlDebugSupport.c

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#include "DebugSupport.h"
 
//
// This the global main table to keep track of the interrupts
//
IDT_ENTRY  *IdtEntryTable = NULL;
 
VOID
ReadIdtGateDescriptor (
  IN  EFI_EXCEPTION_TYPE        Vector,
  OUT IA32_IDT_GATE_DESCRIPTOR  *IdtGateDescriptor
  )
{
  IA32_DESCRIPTOR           IdtrValue;
  IA32_IDT_GATE_DESCRIPTOR  *IdtTable;
 
  AsmReadIdtr (&IdtrValue);
  IdtTable = (IA32_IDT_GATE_DESCRIPTOR *)IdtrValue.Base;
 
  CopyMem ((VOID *)IdtGateDescriptor, (VOID *)&(IdtTable)[Vector], sizeof (IA32_IDT_GATE_DESCRIPTOR));
}
 
VOID
WriteIdtGateDescriptor (
  EFI_EXCEPTION_TYPE        Vector,
  IA32_IDT_GATE_DESCRIPTOR  *IdtGateDescriptor
  )
{
  IA32_DESCRIPTOR           IdtrValue;
  IA32_IDT_GATE_DESCRIPTOR  *IdtTable;
 
  AsmReadIdtr (&IdtrValue);
  IdtTable = (IA32_IDT_GATE_DESCRIPTOR *)IdtrValue.Base;
 
  CopyMem ((VOID *)&(IdtTable)[Vector], (VOID *)IdtGateDescriptor, sizeof (IA32_IDT_GATE_DESCRIPTOR));
}
 
VOID
HookEntry (
  IN EFI_EXCEPTION_TYPE  ExceptionType,
  IN CALLBACK_FUNC       NewCallback
  )
{
  BOOLEAN  OldIntFlagState;
 
  CreateEntryStub (ExceptionType, (VOID **)&IdtEntryTable[ExceptionType].StubEntry);
 
  //
  // Disables CPU interrupts and returns the previous interrupt state
  //
  OldIntFlagState = SaveAndDisableInterrupts ();
 
  //
  // gets IDT Gate descriptor by index
  //
  ReadIdtGateDescriptor (ExceptionType, &(IdtEntryTable[ExceptionType].OrigDesc));
  //
  // stores orignal interrupt handle
  //
  IdtEntryTable[ExceptionType].OrigVector = (DEBUG_PROC)GetInterruptHandleFromIdt (&(IdtEntryTable[ExceptionType].OrigDesc));
 
  //
  // encodes new IDT Gate descriptor by stub entry
  //
  Vect2Desc (&IdtEntryTable[ExceptionType].NewDesc, IdtEntryTable[ExceptionType].StubEntry);
  //
  // stores NewCallback
  //
  IdtEntryTable[ExceptionType].RegisteredCallback = NewCallback;
 
  //
  // writes back new IDT Gate descriptor
  //
  WriteIdtGateDescriptor (ExceptionType, &(IdtEntryTable[ExceptionType].NewDesc));
 
  //
  // restore interrupt state
  //
  SetInterruptState (OldIntFlagState);
 
  return;
}
 
VOID
UnhookEntry (
  IN EFI_EXCEPTION_TYPE  ExceptionType
  )
{
  BOOLEAN  OldIntFlagState;
 
  //
  // Disables CPU interrupts and returns the previous interrupt state
  //
  OldIntFlagState = SaveAndDisableInterrupts ();
 
  //
  // restore the default IDT Date Descriptor
  //
  WriteIdtGateDescriptor (ExceptionType, &(IdtEntryTable[ExceptionType].OrigDesc));
 
  //
  // restore interrupt state
  //
  SetInterruptState (OldIntFlagState);
 
  return;
}
 
EFI_STATUS
EFIAPI
GetMaximumProcessorIndex (
  IN EFI_DEBUG_SUPPORT_PROTOCOL  *This,
  OUT UINTN                      *MaxProcessorIndex
  )
{
  *MaxProcessorIndex = 0;
  return EFI_SUCCESS;
}
 
EFI_STATUS
EFIAPI
RegisterPeriodicCallback (
  IN EFI_DEBUG_SUPPORT_PROTOCOL  *This,
  IN UINTN                       ProcessorIndex,
  IN EFI_PERIODIC_CALLBACK       PeriodicCallback
  )
{
  return ManageIdtEntryTable (PeriodicCallback, SYSTEM_TIMER_VECTOR);
}
 
EFI_STATUS
EFIAPI
RegisterExceptionCallback (
  IN EFI_DEBUG_SUPPORT_PROTOCOL  *This,
  IN UINTN                       ProcessorIndex,
  IN EFI_EXCEPTION_CALLBACK      ExceptionCallback,
  IN EFI_EXCEPTION_TYPE          ExceptionType
  )
{
  return ManageIdtEntryTable (ExceptionCallback, ExceptionType);
}
 
EFI_STATUS
EFIAPI
InvalidateInstructionCache (
  IN EFI_DEBUG_SUPPORT_PROTOCOL  *This,
  IN UINTN                       ProcessorIndex,
  IN VOID                        *Start,
  IN UINT64                      Length
  )
{
  AsmWbinvd ();
  return EFI_SUCCESS;
}
 
VOID
InterruptDistrubutionHub (
  EFI_EXCEPTION_TYPE       ExceptionType,
  EFI_SYSTEM_CONTEXT_IA32  *ContextRecord
  )
{
  if (IdtEntryTable[ExceptionType].RegisteredCallback != NULL) {
    if (ExceptionType != SYSTEM_TIMER_VECTOR) {
      IdtEntryTable[ExceptionType].RegisteredCallback (ExceptionType, ContextRecord);
    } else {
      OrigVector = IdtEntryTable[ExceptionType].OrigVector;
      IdtEntryTable[ExceptionType].RegisteredCallback (ContextRecord);
    }
  }
}
 
EFI_STATUS
EFIAPI
PlUnloadDebugSupportDriver (
  IN EFI_HANDLE  ImageHandle
  )
{
  EFI_EXCEPTION_TYPE  ExceptionType;
 
  for (ExceptionType = 0; ExceptionType < NUM_IDT_ENTRIES; ExceptionType++) {
    ManageIdtEntryTable (NULL, ExceptionType);
    //
    // Free space for each Interrupt Stub precedure.
    //
    if (IdtEntryTable[ExceptionType].StubEntry != NULL) {
      FreePool ((VOID *)(UINTN)IdtEntryTable[ExceptionType].StubEntry);
    }
  }
 
  FreePool (IdtEntryTable);
 
  return EFI_SUCCESS;
}
 
EFI_STATUS
PlInitializeDebugSupportDriver (
  VOID
  )
{
  EFI_EXCEPTION_TYPE  ExceptionType;
 
  //
  // Check whether FxStor instructions are supported.
  //
  if (!FxStorSupport ()) {
    return EFI_UNSUPPORTED;
  }
 
  IdtEntryTable = AllocateZeroPool (sizeof (IDT_ENTRY) * NUM_IDT_ENTRIES);
  if (IdtEntryTable == NULL) {
    return EFI_OUT_OF_RESOURCES;
  }
 
  for (ExceptionType = 0; ExceptionType < NUM_IDT_ENTRIES; ExceptionType++) {
    IdtEntryTable[ExceptionType].StubEntry = (DEBUG_PROC)(UINTN)AllocatePool (StubSize);
    if (IdtEntryTable[ExceptionType].StubEntry == NULL) {
      goto ErrorCleanup;
    }
 
    //
    // Copy Interrupt stub code.
    //
    CopyMem ((VOID *)(UINTN)IdtEntryTable[ExceptionType].StubEntry, InterruptEntryStub, StubSize);
  }
 
  return EFI_SUCCESS;
 
ErrorCleanup:
 
  for (ExceptionType = 0; ExceptionType < NUM_IDT_ENTRIES; ExceptionType++) {
    if (IdtEntryTable[ExceptionType].StubEntry != NULL) {
      FreePool ((VOID *)(UINTN)IdtEntryTable[ExceptionType].StubEntry);
    }
  }
 
  FreePool (IdtEntryTable);
 
  return EFI_OUT_OF_RESOURCES;
}