DuetPkg/BiosVideoThunkDxe/LegacyBiosThunk.c

   1
   2 #include "BiosVideo.h"
   3
   4 #define EFI_CPU_EFLAGS_IF 0x200
   5
   6 THUNK_CONTEXT               mThunkContext;
   7
   8 VOID
   9 InitializeBiosIntCaller (
  10   IN  BIOS_VIDEO_DEV                 *BiosDev
  11   )
  12 {
  13   EFI_STATUS            Status;
  14   UINT32                RealModeBufferSize;
  15   UINT32                ExtraStackSize;
  16   EFI_PHYSICAL_ADDRESS  LegacyRegionBase;
  17
  18   //
  19   // Get LegacyRegion
  20   //
  21   AsmGetThunk16Properties (&RealModeBufferSize, &ExtraStackSize);
  22
  23   LegacyRegionBase = 0x100000;
  24   Status = gBS->AllocatePages (
  25                   AllocateMaxAddress,
  26                   EfiACPIMemoryNVS,
  27                   EFI_SIZE_TO_PAGES(RealModeBufferSize + ExtraStackSize + 200),
  28                   &LegacyRegionBase
  29                   );
  30   ASSERT_EFI_ERROR (Status);
  31
  32   mThunkContext.RealModeBuffer     = (VOID*)(UINTN)LegacyRegionBase;
  33   mThunkContext.RealModeBufferSize = EFI_PAGES_TO_SIZE (RealModeBufferSize);
  34   mThunkContext.ThunkAttributes    = 3;
  35   AsmPrepareThunk16(&mThunkContext);
  36
  37 }
  38
  39 VOID
  40 InitializeInterruptRedirection (
  41   IN  BIOS_VIDEO_DEV                 *BiosDev
  42   )
  43 /*++
  44
  45   Routine Description:
  46     Initialize interrupt redirection code and entries, because
  47     IDT Vectors 0x68-0x6f must be redirected to IDT Vectors 0x08-0x0f.
  48     Or the interrupt will lost when we do thunk.
  49     NOTE: We do not reset 8259 vector base, because it will cause pending
  50     interrupt lost.
  51
  52   Arguments:
  53     NONE
  54
  55   Returns:
  56     NONE
  57 --*/
  58 {
  59   EFI_STATUS            Status;
  60   EFI_PHYSICAL_ADDRESS  LegacyRegionBase;
  61   UINTN                 LegacyRegionLength;
  62   UINT32                *IdtArray;
  63   UINTN                 Index;
  64   UINT8                 ProtectedModeBaseVector;
  65   UINT32                InterruptRedirectionCode[] = {
  66     0x90CF08CD, // INT8; IRET; NOP
  67     0x90CF09CD, // INT9; IRET; NOP
  68     0x90CF0ACD, // INTA; IRET; NOP
  69     0x90CF0BCD, // INTB; IRET; NOP
  70     0x90CF0CCD, // INTC; IRET; NOP
  71     0x90CF0DCD, // INTD; IRET; NOP
  72     0x90CF0ECD, // INTE; IRET; NOP
  73     0x90CF0FCD  // INTF; IRET; NOP
  74   };
  75
  76   //
  77   // Get LegacyRegion
  78   //
  79   LegacyRegionLength = sizeof(InterruptRedirectionCode);
  80   LegacyRegionBase = 0x100000;
  81   Status = gBS->AllocatePages (
  82                   AllocateMaxAddress,
  83                   EfiACPIMemoryNVS,
  84                   EFI_SIZE_TO_PAGES(LegacyRegionLength),
  85                   &LegacyRegionBase
  86                   );
  87   ASSERT_EFI_ERROR (Status);
  88
  89   //
  90   // Copy code to legacy region
  91   //
  92   CopyMem ((VOID *)(UINTN)LegacyRegionBase, InterruptRedirectionCode, sizeof (InterruptRedirectionCode));
  93
  94   //
  95   // Get VectorBase, it should be 0x68
  96   //
  97   Status = BiosDev->Legacy8259->GetVector (BiosDev->Legacy8259, Efi8259Irq0, &ProtectedModeBaseVector);
  98   ASSERT_EFI_ERROR (Status);
  99
 100   //
 101   // Patch IVT 0x68 ~ 0x6f
 102   //
 103   IdtArray = (UINT32 *) 0;
 104   for (Index = 0; Index < 8; Index++) {
 105     IdtArray[ProtectedModeBaseVector + Index] = ((EFI_SEGMENT (LegacyRegionBase + Index * 4)) << 16) | (EFI_OFFSET (LegacyRegionBase + Index * 4));
 106   }
 107
 108   return ;
 109 }
 110
 111 BOOLEAN
 112 EFIAPI
 113 LegacyBiosInt86 (
 114   IN  BIOS_VIDEO_DEV                 *BiosDev,
 115   IN  UINT8                           BiosInt,
 116   IN  EFI_IA32_REGISTER_SET           *Regs
 117   )
 118 /*++
 119
 120   Routine Description:
 121     Thunk to 16-bit real mode and execute a software interrupt with a vector
 122     of BiosInt. Regs will contain the 16-bit register context on entry and
 123     exit.
 124
 125   Arguments:
 126     This    - Protocol instance pointer.
 127     BiosInt - Processor interrupt vector to invoke
 128     Reg     - Register contexted passed into (and returned) from thunk to
 129               16-bit mode
 130
 131   Returns:
 132     FALSE   - Thunk completed, and there were no BIOS errors in the target code.
 133               See Regs for status.
 134     TRUE    - There was a BIOS erro in the target code.
 135
 136 --*/
 137 {
 138   UINTN                 Status;
 139   UINTN                 Eflags;
 140   IA32_REGISTER_SET     ThunkRegSet;
 141   BOOLEAN               Ret;
 142   UINT16                *Stack16;
 143
 144   Regs->X.Flags.Reserved1 = 1;
 145   Regs->X.Flags.Reserved2 = 0;
 146   Regs->X.Flags.Reserved3 = 0;
 147   Regs->X.Flags.Reserved4 = 0;
 148   Regs->X.Flags.IOPL      = 3;
 149   Regs->X.Flags.NT        = 0;
 150   Regs->X.Flags.IF        = 1;
 151   Regs->X.Flags.TF        = 0;
 152   Regs->X.Flags.CF        = 0;
 153
 154   ZeroMem (&ThunkRegSet, sizeof (ThunkRegSet));
 155   ThunkRegSet.E.EDI  = Regs->E.EDI;
 156   ThunkRegSet.E.ESI  = Regs->E.ESI;
 157   ThunkRegSet.E.EBP  = Regs->E.EBP;
 158   ThunkRegSet.E.EBX  = Regs->E.EBX;
 159   ThunkRegSet.E.EDX  = Regs->E.EDX;
 160   ThunkRegSet.E.ECX  = Regs->E.ECX;
 161   ThunkRegSet.E.EAX  = Regs->E.EAX;
 162   ThunkRegSet.E.DS   = Regs->E.DS;
 163   ThunkRegSet.E.ES   = Regs->E.ES;
 164
 165   CopyMem (&(ThunkRegSet.E.EFLAGS), &(Regs->E.EFlags), sizeof (UINT32));
 166
 167   //
 168   // The call to Legacy16 is a critical section to EFI
 169   //
 170   Eflags = AsmReadEflags ();
 171   if ((Eflags | EFI_CPU_EFLAGS_IF) != 0) {
 172     DisableInterrupts ();
 173   }
 174
 175   //
 176   // Set Legacy16 state. 0x08, 0x70 is legacy 8259 vector bases.
 177   //
 178   Status = BiosDev->Legacy8259->SetMode (BiosDev->Legacy8259, Efi8259LegacyMode, NULL, NULL);
 179   ASSERT_EFI_ERROR (Status);
 180
 181   Stack16 = (UINT16 *)((UINT8 *) mThunkContext.RealModeBuffer + mThunkContext.RealModeBufferSize - sizeof (UINT16));
 182   Stack16 -= sizeof (ThunkRegSet.E.EFLAGS) / sizeof (UINT16);
 183   CopyMem (Stack16, &ThunkRegSet.E.EFLAGS, sizeof (ThunkRegSet.E.EFLAGS));
 184
 185   ThunkRegSet.E.SS   = (UINT16) (((UINTN) Stack16 >> 16) << 12);
 186   ThunkRegSet.E.ESP  = (UINT16) (UINTN) Stack16;
 187   ThunkRegSet.E.Eip  = (UINT16)((UINT32 *)NULL)[BiosInt];
 188   ThunkRegSet.E.CS   = (UINT16)(((UINT32 *)NULL)[BiosInt] >> 16);
 189   mThunkContext.RealModeState = &ThunkRegSet;
 190   AsmThunk16 (&mThunkContext);
 191
 192   //
 193   // Restore protected mode interrupt state
 194   //
 195   Status = BiosDev->Legacy8259->SetMode (BiosDev->Legacy8259, Efi8259ProtectedMode, NULL, NULL);
 196   ASSERT_EFI_ERROR (Status);
 197
 198   //
 199   // End critical section
 200   //
 201   if ((Eflags | EFI_CPU_EFLAGS_IF) != 0) {
 202     EnableInterrupts ();
 203   }
 204
 205   Regs->E.EDI      = ThunkRegSet.E.EDI;
 206   Regs->E.ESI      = ThunkRegSet.E.ESI;
 207   Regs->E.EBP      = ThunkRegSet.E.EBP;
 208   Regs->E.EBX      = ThunkRegSet.E.EBX;
 209   Regs->E.EDX      = ThunkRegSet.E.EDX;
 210   Regs->E.ECX      = ThunkRegSet.E.ECX;
 211   Regs->E.EAX      = ThunkRegSet.E.EAX;
 212   Regs->E.SS       = ThunkRegSet.E.SS;
 213   Regs->E.CS       = ThunkRegSet.E.CS;
 214   Regs->E.DS       = ThunkRegSet.E.DS;
 215   Regs->E.ES       = ThunkRegSet.E.ES;
 216
 217   CopyMem (&(Regs->E.EFlags), &(ThunkRegSet.E.EFLAGS), sizeof (UINT32));
 218
 219   Ret = (BOOLEAN) (Regs->E.EFlags.CF == 1);
 220
 221   return Ret;
 222 }
 223
 224