MmSaveStateCommon.c

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#include "MmSaveState.h"
 
// Table used by MmSaveStateGetRegisterIndex() to convert an EFI_MM_SAVE_STATE_REGISTER
// value to an index into a table of type CPU_MM_SAVE_STATE_LOOKUP_ENTRY
CONST CPU_MM_SAVE_STATE_REGISTER_RANGE  mCpuRegisterRanges[] = {
  MM_REGISTER_RANGE (EFI_MM_SAVE_STATE_REGISTER_GDTBASE, EFI_MM_SAVE_STATE_REGISTER_LDTINFO),
  MM_REGISTER_RANGE (EFI_MM_SAVE_STATE_REGISTER_ES,      EFI_MM_SAVE_STATE_REGISTER_RIP),
  MM_REGISTER_RANGE (EFI_MM_SAVE_STATE_REGISTER_RFLAGS,  EFI_MM_SAVE_STATE_REGISTER_CR4),
  { (EFI_MM_SAVE_STATE_REGISTER)0,                       (EFI_MM_SAVE_STATE_REGISTER)0,      0}
};
 
extern CONST CPU_MM_SAVE_STATE_LOOKUP_ENTRY  mCpuWidthOffset[];
 
UINTN
MmSaveStateGetRegisterIndex (
  IN EFI_MM_SAVE_STATE_REGISTER  Register,
  IN UINTN                       RegOffset
  )
{
  UINTN  Index;
  UINTN  Offset;
 
  for (Index = 0, Offset = RegOffset; mCpuRegisterRanges[Index].Length != 0; Index++) {
    if ((Register >= mCpuRegisterRanges[Index].Start) && (Register <= mCpuRegisterRanges[Index].End)) {
      return Register - mCpuRegisterRanges[Index].Start + Offset;
    }
 
    Offset += mCpuRegisterRanges[Index].Length;
  }
 
  return 0;
}
 
EFI_STATUS
MmSaveStateReadRegisterByIndex (
  IN UINTN  CpuIndex,
  IN UINTN  RegisterIndex,
  IN UINTN  Width,
  OUT VOID  *Buffer
  )
{
  if (RegisterIndex == 0) {
    return EFI_NOT_FOUND;
  }
 
  if (MmSaveStateGetRegisterLma () == EFI_MM_SAVE_STATE_REGISTER_LMA_32BIT) {
    //
    // If 32-bit mode width is zero, then the specified register can not be accessed
    //
    if (mCpuWidthOffset[RegisterIndex].Width32 == 0) {
      return EFI_NOT_FOUND;
    }
 
    //
    // If Width is bigger than the 32-bit mode width, then the specified register can not be accessed
    //
    if (Width > mCpuWidthOffset[RegisterIndex].Width32) {
      return EFI_INVALID_PARAMETER;
    }
 
    //
    // Write return buffer
    //
    ASSERT (gMmst->CpuSaveState[CpuIndex] != NULL);
    CopyMem (Buffer, (UINT8 *)gMmst->CpuSaveState[CpuIndex] + mCpuWidthOffset[RegisterIndex].Offset32, Width);
  } else {
    //
    // If 64-bit mode width is zero, then the specified register can not be accessed
    //
    if (mCpuWidthOffset[RegisterIndex].Width64 == 0) {
      return EFI_NOT_FOUND;
    }
 
    //
    // If Width is bigger than the 64-bit mode width, then the specified register can not be accessed
    //
    if (Width > mCpuWidthOffset[RegisterIndex].Width64) {
      return EFI_INVALID_PARAMETER;
    }
 
    //
    // Write lower 32-bits of return buffer
    //
    CopyMem (Buffer, (UINT8 *)gMmst->CpuSaveState[CpuIndex] + mCpuWidthOffset[RegisterIndex].Offset64Lo, MIN (4, Width));
    if (Width > 4) {
      //
      // Write upper 32-bits of return buffer
      //
      CopyMem ((UINT8 *)Buffer + 4, (UINT8 *)gMmst->CpuSaveState[CpuIndex] + mCpuWidthOffset[RegisterIndex].Offset64Hi, Width - 4);
    }
  }
 
  return EFI_SUCCESS;
}