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   UINT32                LegacyRegionSize;
  34   //
  35   // Get LegacyRegion
  36   //
  37   AsmGetThunk16Properties (&RealModeBufferSize, &ExtraStackSize);
  38   LegacyRegionSize = (((RealModeBufferSize + ExtraStackSize) / EFI_PAGE_SIZE) + 1) * EFI_PAGE_SIZE;
  39   LegacyRegionBase = 0x100000;
  40   Status = gBS->AllocatePages (
  41                   AllocateMaxAddress,
  42                   EfiACPIMemoryNVS,
  43                   EFI_SIZE_TO_PAGES(LegacyRegionSize),
  44                   &LegacyRegionBase
  45                   );
  46   ASSERT_EFI_ERROR (Status);
  47
  48   ThunkContext->RealModeBuffer     = (VOID*)(UINTN)LegacyRegionBase;
  49   ThunkContext->RealModeBufferSize = LegacyRegionSize;
  50   ThunkContext->ThunkAttributes    = THUNK_ATTRIBUTE_BIG_REAL_MODE|THUNK_ATTRIBUTE_DISABLE_A20_MASK_INT_15;
  51   AsmPrepareThunk16(ThunkContext);
  52 }
  53
  54 /**
  55    Initialize interrupt redirection code and entries, because
  56    IDT Vectors 0x68-0x6f must be redirected to IDT Vectors 0x08-0x0f.
  57    Or the interrupt will lost when we do thunk.
  58    NOTE: We do not reset 8259 vector base, because it will cause pending
  59    interrupt lost.
  60
  61    @param Legacy8259  Instance pointer for EFI_LEGACY_8259_PROTOCOL.
  62
  63 **/
  64 VOID
  65 InitializeInterruptRedirection (
  66   IN  EFI_LEGACY_8259_PROTOCOL  *Legacy8259
  67   )
  68 {
  69   EFI_STATUS            Status;
  70   EFI_PHYSICAL_ADDRESS  LegacyRegionBase;
  71   UINTN                 LegacyRegionLength;
  72   UINT32                *IdtArray;
  73   UINTN                 Index;
  74   UINT8                 ProtectedModeBaseVector;
  75   UINT32                InterruptRedirectionCode[] = {
  76     0x90CF08CD, // INT8; IRET; NOP
  77     0x90CF09CD, // INT9; IRET; NOP
  78     0x90CF0ACD, // INTA; IRET; NOP
  79     0x90CF0BCD, // INTB; IRET; NOP
  80     0x90CF0CCD, // INTC; IRET; NOP
  81     0x90CF0DCD, // INTD; IRET; NOP
  82     0x90CF0ECD, // INTE; IRET; NOP
  83     0x90CF0FCD  // INTF; IRET; NOP
  84   };
  85
  86   //
  87   // Get LegacyRegion
  88   //
  89   LegacyRegionLength = sizeof(InterruptRedirectionCode);
  90   LegacyRegionBase = 0x100000;
  91   Status = gBS->AllocatePages (
  92                   AllocateMaxAddress,
  93                   EfiACPIMemoryNVS,
  94                   EFI_SIZE_TO_PAGES(LegacyRegionLength),
  95                   &LegacyRegionBase
  96                   );
  97   ASSERT_EFI_ERROR (Status);
  98
  99   //
 100   // Copy code to legacy region
 101   //
 102   CopyMem ((VOID *)(UINTN)LegacyRegionBase, InterruptRedirectionCode, sizeof (InterruptRedirectionCode));
 103
 104   //
 105   // Get VectorBase, it should be 0x68
 106   //
 107   Status = Legacy8259->GetVector (Legacy8259, Efi8259Irq0, &ProtectedModeBaseVector);
 108   ASSERT_EFI_ERROR (Status);
 109
 110   //
 111   // Patch IVT 0x68 ~ 0x6f
 112   //
 113   IdtArray = (UINT32 *) 0;
 114   for (Index = 0; Index < 8; Index++) {
 115     IdtArray[ProtectedModeBaseVector + Index] = ((EFI_SEGMENT (LegacyRegionBase + Index * 4)) << 16) | (EFI_OFFSET (LegacyRegionBase + Index * 4));
 116   }
 117
 118   return ;
 119 }
 120
 121 /**
 122   Thunk to 16-bit real mode and execute a software interrupt with a vector
 123   of BiosInt. Regs will contain the 16-bit register context on entry and
 124   exit.
 125
 126   @param  This    Protocol instance pointer.
 127   @param  BiosInt Processor interrupt vector to invoke
 128   @param  Reg     Register contexted passed into (and returned) from thunk to 16-bit mode
 129
 130   @retval TRUE   Thunk completed, and there were no BIOS errors in the target code.
 131                  See Regs for status.
 132   @retval FALSE  There was a BIOS erro in the target code.
 133 **/
 134 BOOLEAN
 135 EFIAPI
 136 LegacyBiosInt86 (
 137   IN  BIOS_VIDEO_DEV                 *BiosDev,
 138   IN  UINT8                           BiosInt,
 139   IN  IA32_REGISTER_SET              *Regs
 140   )
 141 {
 142   UINTN                 Status;
 143   UINTN                 Eflags;
 144   IA32_REGISTER_SET     ThunkRegSet;
 145   BOOLEAN               Ret;
 146   UINT16                *Stack16;
 147
 148   ZeroMem (&ThunkRegSet, sizeof (ThunkRegSet));
 149   ThunkRegSet.E.EFLAGS.Bits.Reserved_0 = 1;
 150   ThunkRegSet.E.EFLAGS.Bits.Reserved_1 = 0;
 151   ThunkRegSet.E.EFLAGS.Bits.Reserved_2 = 0;
 152   ThunkRegSet.E.EFLAGS.Bits.Reserved_3 = 0;
 153   ThunkRegSet.E.EFLAGS.Bits.IOPL       = 3;
 154   ThunkRegSet.E.EFLAGS.Bits.NT         = 0;
 155   ThunkRegSet.E.EFLAGS.Bits.IF         = 1;
 156   ThunkRegSet.E.EFLAGS.Bits.TF         = 0;
 157   ThunkRegSet.E.EFLAGS.Bits.CF         = 0;
 158
 159   ThunkRegSet.E.EDI  = Regs->E.EDI;
 160   ThunkRegSet.E.ESI  = Regs->E.ESI;
 161   ThunkRegSet.E.EBP  = Regs->E.EBP;
 162   ThunkRegSet.E.EBX  = Regs->E.EBX;
 163   ThunkRegSet.E.EDX  = Regs->E.EDX;
 164   ThunkRegSet.E.ECX  = Regs->E.ECX;
 165   ThunkRegSet.E.EAX  = Regs->E.EAX;
 166   ThunkRegSet.E.DS   = Regs->E.DS;
 167   ThunkRegSet.E.ES   = Regs->E.ES;
 168
 169   //
 170   // The call to Legacy16 is a critical section to EFI
 171   //
 172   Eflags = AsmReadEflags ();
 173   if ((Eflags | EFI_CPU_EFLAGS_IF) != 0) {
 174     DisableInterrupts ();
 175   }
 176
 177   //
 178   // Set Legacy16 state. 0x08, 0x70 is legacy 8259 vector bases.
 179   //
 180   Status = BiosDev->Legacy8259->SetMode (BiosDev->Legacy8259, Efi8259LegacyMode, NULL, NULL);
 181   ASSERT_EFI_ERROR (Status);
 182
 183   Stack16 = (UINT16 *)((UINT8 *) BiosDev->ThunkContext->RealModeBuffer + BiosDev->ThunkContext->RealModeBufferSize - sizeof (UINT16));
 184
 185   ThunkRegSet.E.SS   = (UINT16) (((UINTN) Stack16 >> 16) << 12);
 186   ThunkRegSet.E.ESP  = (UINT16) (UINTN) Stack16;
 187
 188   ThunkRegSet.E.Eip  = (UINT16)((UINT32 *)NULL)[BiosInt];
 189   ThunkRegSet.E.CS   = (UINT16)(((UINT32 *)NULL)[BiosInt] >> 16);
 190   BiosDev->ThunkContext->RealModeState = &ThunkRegSet;
 191   AsmThunk16 (BiosDev->ThunkContext);
 192
 193   //
 194   // Restore protected mode interrupt state
 195   //
 196   Status = BiosDev->Legacy8259->SetMode (BiosDev->Legacy8259, Efi8259ProtectedMode, NULL, NULL);
 197   ASSERT_EFI_ERROR (Status);
 198
 199   //
 200   // End critical section
 201   //
 202   if ((Eflags | EFI_CPU_EFLAGS_IF) != 0) {
 203     EnableInterrupts ();
 204   }
 205
 206   Regs->E.EDI      = ThunkRegSet.E.EDI;
 207   Regs->E.ESI      = ThunkRegSet.E.ESI;
 208   Regs->E.EBP      = ThunkRegSet.E.EBP;
 209   Regs->E.EBX      = ThunkRegSet.E.EBX;
 210   Regs->E.EDX      = ThunkRegSet.E.EDX;
 211   Regs->E.ECX      = ThunkRegSet.E.ECX;
 212   Regs->E.EAX      = ThunkRegSet.E.EAX;
 213   Regs->E.SS       = ThunkRegSet.E.SS;
 214   Regs->E.CS       = ThunkRegSet.E.CS;
 215   Regs->E.DS       = ThunkRegSet.E.DS;
 216   Regs->E.ES       = ThunkRegSet.E.ES;
 217
 218   CopyMem (&(Regs->E.EFLAGS), &(ThunkRegSet.E.EFLAGS), sizeof (UINT32));
 219
 220   Ret = (BOOLEAN) (Regs->E.EFLAGS.Bits.CF == 1);
 221
 222   return Ret;
 223 }
 224
 225