DuetPkg/BiosVideoThunkDxe/LegacyBiosThunk.c

   1 /** @file
   2   Provide legacy thunk interface for accessing Bios Video Rom.
   3
   4 Copyright (c) 2006 - 2007, Intel Corporation
   5 All rights reserved. This program and the accompanying materials
   6 are licensed and made available under the terms and conditions of the BSD License
   7 which accompanies this distribution.  The full text of the license may be found at
   8 http://opensource.org/licenses/bsd-license.php
   9
  10 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  11 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  12
  13 **/
  14
  15 #include "BiosVideo.h"
  16
  17 #define EFI_CPU_EFLAGS_IF 0x200
  18
  19 /**
  20   Initialize legacy environment for BIOS INI caller.
  21
  22   @param ThunkContext   the instance pointer of THUNK_CONTEXT
  23 **/
  24 VOID
  25 InitializeBiosIntCaller (
  26   THUNK_CONTEXT     *ThunkContext
  27   )
  28 {
  29   EFI_STATUS            Status;
  30   UINT32                RealModeBufferSize;
  31   UINT32                ExtraStackSize;
  32   EFI_PHYSICAL_ADDRESS  LegacyRegionBase;
  33
  34   //
  35   // Get LegacyRegion
  36   //
  37   AsmGetThunk16Properties (&RealModeBufferSize, &ExtraStackSize);
  38
  39   LegacyRegionBase = 0x100000;
  40   Status = gBS->AllocatePages (
  41                   AllocateMaxAddress,
  42                   EfiACPIMemoryNVS,
  43                   EFI_SIZE_TO_PAGES(RealModeBufferSize + ExtraStackSize + 200),
  44                   &LegacyRegionBase
  45                   );
  46   ASSERT_EFI_ERROR (Status);
  47
  48   ThunkContext->RealModeBuffer     = (VOID*)(UINTN)LegacyRegionBase;
  49   ThunkContext->RealModeBufferSize = EFI_PAGES_TO_SIZE (RealModeBufferSize);
  50   ThunkContext->ThunkAttributes    = 3;
  51   AsmPrepareThunk16(ThunkContext);
  52
  53 }
  54
  55 /**
  56    Initialize interrupt redirection code and entries, because
  57    IDT Vectors 0x68-0x6f must be redirected to IDT Vectors 0x08-0x0f.
  58    Or the interrupt will lost when we do thunk.
  59    NOTE: We do not reset 8259 vector base, because it will cause pending
  60    interrupt lost.
  61
  62    @param Legacy8259  Instance pointer for EFI_LEGACY_8259_PROTOCOL.
  63
  64 **/
  65 VOID
  66 InitializeInterruptRedirection (
  67   IN  EFI_LEGACY_8259_PROTOCOL  *Legacy8259
  68   )
  69 {
  70   EFI_STATUS            Status;
  71   EFI_PHYSICAL_ADDRESS  LegacyRegionBase;
  72   UINTN                 LegacyRegionLength;
  73   UINT32                *IdtArray;
  74   UINTN                 Index;
  75   UINT8                 ProtectedModeBaseVector;
  76   UINT32                InterruptRedirectionCode[] = {
  77     0x90CF08CD, // INT8; IRET; NOP
  78     0x90CF09CD, // INT9; IRET; NOP
  79     0x90CF0ACD, // INTA; IRET; NOP
  80     0x90CF0BCD, // INTB; IRET; NOP
  81     0x90CF0CCD, // INTC; IRET; NOP
  82     0x90CF0DCD, // INTD; IRET; NOP
  83     0x90CF0ECD, // INTE; IRET; NOP
  84     0x90CF0FCD  // INTF; IRET; NOP
  85   };
  86
  87   //
  88   // Get LegacyRegion
  89   //
  90   LegacyRegionLength = sizeof(InterruptRedirectionCode);
  91   LegacyRegionBase = 0x100000;
  92   Status = gBS->AllocatePages (
  93                   AllocateMaxAddress,
  94                   EfiACPIMemoryNVS,
  95                   EFI_SIZE_TO_PAGES(LegacyRegionLength),
  96                   &LegacyRegionBase
  97                   );
  98   ASSERT_EFI_ERROR (Status);
  99
 100   //
 101   // Copy code to legacy region
 102   //
 103   CopyMem ((VOID *)(UINTN)LegacyRegionBase, InterruptRedirectionCode, sizeof (InterruptRedirectionCode));
 104
 105   //
 106   // Get VectorBase, it should be 0x68
 107   //
 108   Status = Legacy8259->GetVector (Legacy8259, Efi8259Irq0, &ProtectedModeBaseVector);
 109   ASSERT_EFI_ERROR (Status);
 110
 111   //
 112   // Patch IVT 0x68 ~ 0x6f
 113   //
 114   IdtArray = (UINT32 *) 0;
 115   for (Index = 0; Index < 8; Index++) {
 116     IdtArray[ProtectedModeBaseVector + Index] = ((EFI_SEGMENT (LegacyRegionBase + Index * 4)) << 16) | (EFI_OFFSET (LegacyRegionBase + Index * 4));
 117   }
 118
 119   return ;
 120 }
 121
 122 /**
 123   Thunk to 16-bit real mode and execute a software interrupt with a vector
 124   of BiosInt. Regs will contain the 16-bit register context on entry and
 125   exit.
 126
 127   @param  This    Protocol instance pointer.
 128   @param  BiosInt Processor interrupt vector to invoke
 129   @param  Reg     Register contexted passed into (and returned) from thunk to 16-bit mode
 130
 131   @retval TRUE   Thunk completed, and there were no BIOS errors in the target code.
 132                  See Regs for status.
 133   @retval FALSE  There was a BIOS erro in the target code.
 134 **/
 135 BOOLEAN
 136 EFIAPI
 137 LegacyBiosInt86 (
 138   IN  BIOS_VIDEO_DEV                 *BiosDev,
 139   IN  UINT8                           BiosInt,
 140   IN  IA32_REGISTER_SET              *Regs
 141   )
 142 {
 143   UINTN                 Status;
 144   UINTN                 Eflags;
 145   IA32_REGISTER_SET     ThunkRegSet;
 146   BOOLEAN               Ret;
 147   UINT16                *Stack16;
 148
 149   ZeroMem (&ThunkRegSet, sizeof (ThunkRegSet));
 150   ThunkRegSet.E.EFLAGS.Bits.Reserved_0 = 1;
 151   ThunkRegSet.E.EFLAGS.Bits.Reserved_1 = 0;
 152   ThunkRegSet.E.EFLAGS.Bits.Reserved_2 = 0;
 153   ThunkRegSet.E.EFLAGS.Bits.Reserved_3 = 0;
 154   ThunkRegSet.E.EFLAGS.Bits.IOPL       = 3;
 155   ThunkRegSet.E.EFLAGS.Bits.NT         = 0;
 156   ThunkRegSet.E.EFLAGS.Bits.IF         = 1;
 157   ThunkRegSet.E.EFLAGS.Bits.TF         = 0;
 158   ThunkRegSet.E.EFLAGS.Bits.CF         = 0;
 159
 160   ThunkRegSet.E.EDI  = Regs->E.EDI;
 161   ThunkRegSet.E.ESI  = Regs->E.ESI;
 162   ThunkRegSet.E.EBP  = Regs->E.EBP;
 163   ThunkRegSet.E.EBX  = Regs->E.EBX;
 164   ThunkRegSet.E.EDX  = Regs->E.EDX;
 165   ThunkRegSet.E.ECX  = Regs->E.ECX;
 166   ThunkRegSet.E.EAX  = Regs->E.EAX;
 167   ThunkRegSet.E.DS   = Regs->E.DS;
 168   ThunkRegSet.E.ES   = Regs->E.ES;
 169
 170   //
 171   // The call to Legacy16 is a critical section to EFI
 172   //
 173   Eflags = AsmReadEflags ();
 174   if ((Eflags | EFI_CPU_EFLAGS_IF) != 0) {
 175     DisableInterrupts ();
 176   }
 177
 178   //
 179   // Set Legacy16 state. 0x08, 0x70 is legacy 8259 vector bases.
 180   //
 181   Status = BiosDev->Legacy8259->SetMode (BiosDev->Legacy8259, Efi8259LegacyMode, NULL, NULL);
 182   ASSERT_EFI_ERROR (Status);
 183
 184   Stack16 = (UINT16 *)((UINT8 *) BiosDev->ThunkContext->RealModeBuffer + BiosDev->ThunkContext->RealModeBufferSize - sizeof (UINT16));
 185
 186   ThunkRegSet.E.SS   = (UINT16) (((UINTN) Stack16 >> 16) << 12);
 187   ThunkRegSet.E.ESP  = (UINT16) (UINTN) Stack16;
 188
 189   ThunkRegSet.E.Eip  = (UINT16)((UINT32 *)NULL)[BiosInt];
 190   ThunkRegSet.E.CS   = (UINT16)(((UINT32 *)NULL)[BiosInt] >> 16);
 191   BiosDev->ThunkContext->RealModeState = &ThunkRegSet;
 192   AsmThunk16 (BiosDev->ThunkContext);
 193
 194   //
 195   // Restore protected mode interrupt state
 196   //
 197   Status = BiosDev->Legacy8259->SetMode (BiosDev->Legacy8259, Efi8259ProtectedMode, NULL, NULL);
 198   ASSERT_EFI_ERROR (Status);
 199
 200   //
 201   // End critical section
 202   //
 203   if ((Eflags | EFI_CPU_EFLAGS_IF) != 0) {
 204     EnableInterrupts ();
 205   }
 206
 207   Regs->E.EDI      = ThunkRegSet.E.EDI;
 208   Regs->E.ESI      = ThunkRegSet.E.ESI;
 209   Regs->E.EBP      = ThunkRegSet.E.EBP;
 210   Regs->E.EBX      = ThunkRegSet.E.EBX;
 211   Regs->E.EDX      = ThunkRegSet.E.EDX;
 212   Regs->E.ECX      = ThunkRegSet.E.ECX;
 213   Regs->E.EAX      = ThunkRegSet.E.EAX;
 214   Regs->E.SS       = ThunkRegSet.E.SS;
 215   Regs->E.CS       = ThunkRegSet.E.CS;
 216   Regs->E.DS       = ThunkRegSet.E.DS;
 217   Regs->E.ES       = ThunkRegSet.E.ES;
 218
 219   CopyMem (&(Regs->E.EFLAGS), &(ThunkRegSet.E.EFLAGS), sizeof (UINT32));
 220
 221   Ret = (BOOLEAN) (Regs->E.EFLAGS.Bits.CF == 1);
 222
 223   return Ret;
 224 }
 225
 226