IntelFrameworkModulePkg/Csm/LegacyBiosDxe/Thunk.c

   1 /** @file
   2   Call into 16-bit BIOS code, Use AsmThunk16 function of BaseLib.
   3
   4 Copyright (c) 2006 - 2018, Intel Corporation. All rights reserved.<BR>
   5
   6 This program and the accompanying materials
   7 are licensed and made available under the terms and conditions
   8 of the BSD License which accompanies this distribution.  The
   9 full text of the license may be found at
  10 http://opensource.org/licenses/bsd-license.php
  11
  12 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  13 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  14
  15 **/
  16
  17 #include "LegacyBiosInterface.h"
  18
  19 THUNK_CONTEXT      mThunkContext;
  20
  21 /**
  22   Sets the counter value for Timer #0 in a legacy 8254 timer.
  23
  24   @param  Count - The 16-bit counter value to program into Timer #0 of the legacy 8254 timer.
  25
  26 **/
  27 VOID
  28 SetPitCount (
  29   IN UINT16  Count
  30   )
  31 {
  32   IoWrite8 (TIMER_CONTROL_PORT, TIMER0_CONTROL_WORD);
  33   IoWrite8 (TIMER0_COUNT_PORT, (UINT8) (Count & 0xFF));
  34   IoWrite8 (TIMER0_COUNT_PORT, (UINT8) ((Count>>8) & 0xFF));
  35 }
  36
  37 /**
  38   Thunk to 16-bit real mode and execute a software interrupt with a vector
  39   of BiosInt. Regs will contain the 16-bit register context on entry and
  40   exit.
  41
  42   @param  This    Protocol instance pointer.
  43   @param  BiosInt Processor interrupt vector to invoke
  44   @param  Regs    Register contexted passed into (and returned) from thunk to
  45                   16-bit mode
  46
  47   @retval FALSE   Thunk completed, and there were no BIOS errors in the target code.
  48                   See Regs for status.
  49   @retval TRUE    There was a BIOS erro in the target code.
  50
  51 **/
  52 BOOLEAN
  53 EFIAPI
  54 LegacyBiosInt86 (
  55   IN  EFI_LEGACY_BIOS_PROTOCOL      *This,
  56   IN  UINT8                         BiosInt,
  57   IN  EFI_IA32_REGISTER_SET         *Regs
  58   )
  59 {
  60   UINT16                Segment;
  61   UINT16                Offset;
  62
  63   Regs->X.Flags.Reserved1 = 1;
  64   Regs->X.Flags.Reserved2 = 0;
  65   Regs->X.Flags.Reserved3 = 0;
  66   Regs->X.Flags.Reserved4 = 0;
  67   Regs->X.Flags.IOPL      = 3;
  68   Regs->X.Flags.NT        = 0;
  69   Regs->X.Flags.IF        = 0;
  70   Regs->X.Flags.TF        = 0;
  71   Regs->X.Flags.CF        = 0;
  72   //
  73   // The base address of legacy interrupt vector table is 0.
  74   // We use this base address to get the legacy interrupt handler.
  75   //
  76   ACCESS_PAGE0_CODE (
  77     Segment               = (UINT16)(((UINT32 *)0)[BiosInt] >> 16);
  78     Offset                = (UINT16)((UINT32 *)0)[BiosInt];
  79   );
  80
  81   return InternalLegacyBiosFarCall (
  82            This,
  83            Segment,
  84            Offset,
  85            Regs,
  86            &Regs->X.Flags,
  87            sizeof (Regs->X.Flags)
  88            );
  89 }
  90
  91 /**
  92   Thunk to 16-bit real mode and call Segment:Offset. Regs will contain the
  93   16-bit register context on entry and exit. Arguments can be passed on
  94   the Stack argument
  95
  96   @param  This                   Protocol instance pointer.
  97   @param  Segment                Segemnt of 16-bit mode call
  98   @param  Offset                 Offset of 16-bit mdoe call
  99   @param  Regs                   Register contexted passed into (and returned) from
 100                                  thunk to  16-bit mode
 101   @param  Stack                  Caller allocated stack used to pass arguments
 102   @param  StackSize              Size of Stack in bytes
 103
 104   @retval FALSE                  Thunk completed, and there were no BIOS errors in
 105                                  the target code. See Regs for status.
 106   @retval TRUE                   There was a BIOS erro in the target code.
 107
 108 **/
 109 BOOLEAN
 110 EFIAPI
 111 LegacyBiosFarCall86 (
 112   IN  EFI_LEGACY_BIOS_PROTOCOL        *This,
 113   IN  UINT16                          Segment,
 114   IN  UINT16                          Offset,
 115   IN  EFI_IA32_REGISTER_SET           *Regs,
 116   IN  VOID                            *Stack,
 117   IN  UINTN                           StackSize
 118   )
 119 {
 120   Regs->X.Flags.Reserved1 = 1;
 121   Regs->X.Flags.Reserved2 = 0;
 122   Regs->X.Flags.Reserved3 = 0;
 123   Regs->X.Flags.Reserved4 = 0;
 124   Regs->X.Flags.IOPL      = 3;
 125   Regs->X.Flags.NT        = 0;
 126   Regs->X.Flags.IF        = 1;
 127   Regs->X.Flags.TF        = 0;
 128   Regs->X.Flags.CF        = 0;
 129
 130   return InternalLegacyBiosFarCall (This, Segment, Offset, Regs, Stack, StackSize);
 131 }
 132
 133 /**
 134   Provide NULL interrupt handler which is used to check
 135   if there is more than one HW interrupt registers with the CPU AP.
 136
 137   @param  InterruptType - The type of interrupt that occured
 138   @param  SystemContext - A pointer to the system context when the interrupt occured
 139
 140 **/
 141 VOID
 142 EFIAPI
 143 LegacyBiosNullInterruptHandler (
 144   IN EFI_EXCEPTION_TYPE   InterruptType,
 145   IN EFI_SYSTEM_CONTEXT   SystemContext
 146   )
 147 {
 148 }
 149
 150 /**
 151   Thunk to 16-bit real mode and call Segment:Offset. Regs will contain the
 152   16-bit register context on entry and exit. Arguments can be passed on
 153   the Stack argument
 154
 155   @param  This       Protocol instance pointer.
 156   @param  Segment    Segemnt of 16-bit mode call
 157   @param  Offset     Offset of 16-bit mdoe call
 158   @param  Regs       Register contexted passed into (and returned) from thunk to
 159                      16-bit mode
 160   @param  Stack      Caller allocated stack used to pass arguments
 161   @param  StackSize  Size of Stack in bytes
 162
 163   @retval FALSE      Thunk completed, and there were no BIOS errors in the target code.
 164                      See Regs for status.
 165   @retval TRUE       There was a BIOS erro in the target code.
 166
 167 **/
 168 BOOLEAN
 169 EFIAPI
 170 InternalLegacyBiosFarCall (
 171   IN  EFI_LEGACY_BIOS_PROTOCOL        *This,
 172   IN  UINT16                          Segment,
 173   IN  UINT16                          Offset,
 174   IN  EFI_IA32_REGISTER_SET           *Regs,
 175   IN  VOID                            *Stack,
 176   IN  UINTN                           StackSize
 177   )
 178 {
 179   UINTN                 Status;
 180   LEGACY_BIOS_INSTANCE  *Private;
 181   UINT16                *Stack16;
 182   EFI_TPL               OriginalTpl;
 183   IA32_REGISTER_SET     ThunkRegSet;
 184   BOOLEAN               InterruptState;
 185   UINT64                TimerPeriod;
 186
 187   Private = LEGACY_BIOS_INSTANCE_FROM_THIS (This);
 188
 189   ZeroMem (&ThunkRegSet, sizeof (ThunkRegSet));
 190   ThunkRegSet.X.DI   = Regs->X.DI;
 191   ThunkRegSet.X.SI   = Regs->X.SI;
 192   ThunkRegSet.X.BP   = Regs->X.BP;
 193   ThunkRegSet.X.BX   = Regs->X.BX;
 194   ThunkRegSet.X.DX   = Regs->X.DX;
 195   //
 196   // Sometimes, ECX is used to pass in 32 bit data. For example, INT 1Ah, AX = B10Dh is
 197   // "PCI BIOS v2.0c + Write Configuration DWORD" and ECX has the dword to write.
 198   //
 199   ThunkRegSet.E.ECX   = Regs->E.ECX;
 200   ThunkRegSet.X.AX   = Regs->X.AX;
 201   ThunkRegSet.E.DS   = Regs->X.DS;
 202   ThunkRegSet.E.ES   = Regs->X.ES;
 203
 204   CopyMem (&(ThunkRegSet.E.EFLAGS.UintN), &(Regs->X.Flags), sizeof (Regs->X.Flags));
 205
 206   //
 207   // Clear the error flag; thunk code may set it. Stack16 should be the high address
 208   // Make Statk16 address the low 16 bit must be not zero.
 209   //
 210   Stack16 = (UINT16 *)((UINT8 *) mThunkContext.RealModeBuffer + mThunkContext.RealModeBufferSize - sizeof (UINT16));
 211
 212   //
 213   // Save current rate of DXE Timer
 214   //
 215   Private->Timer->GetTimerPeriod (Private->Timer, &TimerPeriod);
 216
 217   //
 218   // Disable DXE Timer while executing in real mode
 219   //
 220   Private->Timer->SetTimerPeriod (Private->Timer, 0);
 221
 222   //
 223   // Save and disable interrupt of debug timer
 224   //
 225   InterruptState = SaveAndSetDebugTimerInterrupt (FALSE);
 226
 227   //
 228   // The call to Legacy16 is a critical section to EFI
 229   //
 230   OriginalTpl = gBS->RaiseTPL (TPL_HIGH_LEVEL);
 231
 232   //
 233   // Check to see if there is more than one HW interrupt registers with the CPU AP.
 234   // If there is, then ASSERT() since that is not compatible with the CSM because
 235   // interupts other than the Timer interrupt that was disabled above can not be
 236   // handled properly from real mode.
 237   //
 238   DEBUG_CODE (
 239     UINTN  Vector;
 240     UINTN  Count;
 241
 242     for (Vector = 0x20, Count = 0; Vector < 0x100; Vector++) {
 243       Status = Private->Cpu->RegisterInterruptHandler (Private->Cpu, Vector, LegacyBiosNullInterruptHandler);
 244       if (Status == EFI_ALREADY_STARTED) {
 245         Count++;
 246       }
 247       if (Status == EFI_SUCCESS) {
 248         Private->Cpu->RegisterInterruptHandler (Private->Cpu, Vector, NULL);
 249       }
 250     }
 251     if (Count >= 2) {
 252       DEBUG ((EFI_D_ERROR, "ERROR: More than one HW interrupt active with CSM enabled\n"));
 253     }
 254     ASSERT (Count < 2);
 255   );
 256
 257   //
 258   // If the Timer AP has enabled the 8254 timer IRQ and the current 8254 timer
 259   // period is less than the CSM required rate of 54.9254, then force the 8254
 260   // PIT counter to 0, which is the CSM required rate of 54.9254 ms
 261   //
 262   if (Private->TimerUses8254 && TimerPeriod < 549254) {
 263     SetPitCount (0);
 264   }
 265
 266   if (Stack != NULL && StackSize != 0) {
 267     //
 268     // Copy Stack to low memory stack
 269     //
 270     Stack16 -= StackSize / sizeof (UINT16);
 271     CopyMem (Stack16, Stack, StackSize);
 272   }
 273
 274   ThunkRegSet.E.SS   = (UINT16) (((UINTN) Stack16 >> 16) << 12);
 275   ThunkRegSet.E.ESP  = (UINT16) (UINTN) Stack16;
 276   ThunkRegSet.E.CS   = Segment;
 277   ThunkRegSet.E.Eip  = Offset;
 278
 279   mThunkContext.RealModeState      = &ThunkRegSet;
 280
 281   //
 282   // Set Legacy16 state. 0x08, 0x70 is legacy 8259 vector bases.
 283   //
 284   Status = Private->Legacy8259->SetMode (Private->Legacy8259, Efi8259LegacyMode, NULL, NULL);
 285   ASSERT_EFI_ERROR (Status);
 286
 287   AsmThunk16 (&mThunkContext);
 288
 289   if (Stack != NULL && StackSize != 0) {
 290     //
 291     // Copy low memory stack to Stack
 292     //
 293     CopyMem (Stack, Stack16, StackSize);
 294   }
 295
 296   //
 297   // Restore protected mode interrupt state
 298   //
 299   Status = Private->Legacy8259->SetMode (Private->Legacy8259, Efi8259ProtectedMode, NULL, NULL);
 300   ASSERT_EFI_ERROR (Status);
 301
 302   mThunkContext.RealModeState = NULL;
 303
 304   //
 305   // Enable and restore rate of DXE Timer
 306   //
 307   Private->Timer->SetTimerPeriod (Private->Timer, TimerPeriod);
 308
 309   //
 310   // End critical section
 311   //
 312   gBS->RestoreTPL (OriginalTpl);
 313
 314   //
 315   // OPROM may allocate EBDA range by itself and change EBDA base and EBDA size.
 316   // Get the current EBDA base address, and compared with pre-allocate minimum
 317   // EBDA base address, if the current EBDA base address is smaller, it indicates
 318   // PcdEbdaReservedMemorySize should be adjusted to larger for more OPROMs.
 319   //
 320   DEBUG_CODE (
 321     {
 322       UINTN                 EbdaBaseAddress;
 323       UINTN                 ReservedEbdaBaseAddress;
 324
 325       ACCESS_PAGE0_CODE (
 326         EbdaBaseAddress = (*(UINT16 *) (UINTN) 0x40E) << 4;
 327         ReservedEbdaBaseAddress = CONVENTIONAL_MEMORY_TOP
 328                                   - PcdGet32 (PcdEbdaReservedMemorySize);
 329         ASSERT (ReservedEbdaBaseAddress <= EbdaBaseAddress);
 330       );
 331     }
 332   );
 333
 334   //
 335   // Restore interrupt of debug timer
 336   //
 337   SaveAndSetDebugTimerInterrupt (InterruptState);
 338
 339   Regs->E.EDI      = ThunkRegSet.E.EDI;
 340   Regs->E.ESI      = ThunkRegSet.E.ESI;
 341   Regs->E.EBP      = ThunkRegSet.E.EBP;
 342   Regs->E.EBX      = ThunkRegSet.E.EBX;
 343   Regs->E.EDX      = ThunkRegSet.E.EDX;
 344   Regs->E.ECX      = ThunkRegSet.E.ECX;
 345   Regs->E.EAX      = ThunkRegSet.E.EAX;
 346   Regs->X.SS       = ThunkRegSet.E.SS;
 347   Regs->X.CS       = ThunkRegSet.E.CS;
 348   Regs->X.DS       = ThunkRegSet.E.DS;
 349   Regs->X.ES       = ThunkRegSet.E.ES;
 350
 351   CopyMem (&(Regs->X.Flags), &(ThunkRegSet.E.EFLAGS.UintN), sizeof (Regs->X.Flags));
 352
 353   return (BOOLEAN) (Regs->X.Flags.CF == 1);
 354 }
 355
 356 /**
 357   Allocate memory < 1 MB and copy the thunker code into low memory. Se up
 358   all the descriptors.
 359
 360   @param  Private                Private context for Legacy BIOS
 361
 362   @retval EFI_SUCCESS            Should only pass.
 363
 364 **/
 365 EFI_STATUS
 366 LegacyBiosInitializeThunk (
 367   IN  LEGACY_BIOS_INSTANCE    *Private
 368   )
 369 {
 370   EFI_STATUS              Status;
 371   EFI_PHYSICAL_ADDRESS    MemoryAddress;
 372   UINT8                   TimerVector;
 373
 374   MemoryAddress   = (EFI_PHYSICAL_ADDRESS) (UINTN) Private->IntThunk;
 375
 376   mThunkContext.RealModeBuffer     = (VOID *) (UINTN) (MemoryAddress + ((sizeof (LOW_MEMORY_THUNK) / EFI_PAGE_SIZE) + 1) * EFI_PAGE_SIZE);
 377   mThunkContext.RealModeBufferSize = EFI_PAGE_SIZE;
 378   mThunkContext.ThunkAttributes    = THUNK_ATTRIBUTE_BIG_REAL_MODE | THUNK_ATTRIBUTE_DISABLE_A20_MASK_INT_15;
 379
 380   AsmPrepareThunk16 (&mThunkContext);
 381
 382   //
 383   // Get the interrupt vector number corresponding to IRQ0 from the 8259 driver
 384   //
 385   TimerVector = 0;
 386   Status = Private->Legacy8259->GetVector (Private->Legacy8259, Efi8259Irq0, &TimerVector);
 387   ASSERT_EFI_ERROR (Status);
 388
 389   //
 390   // Check to see if the Timer AP has hooked the IRQ0 from the 8254 PIT
 391   //
 392   Status = Private->Cpu->RegisterInterruptHandler (
 393                            Private->Cpu,
 394                            TimerVector,
 395                            LegacyBiosNullInterruptHandler
 396                            );
 397   if (Status == EFI_SUCCESS) {
 398     //
 399     // If the Timer AP has not enabled the 8254 timer IRQ, then force the 8254 PIT
 400     // counter to 0, which is the CSM required rate of 54.9254 ms
 401     //
 402     Private->Cpu->RegisterInterruptHandler (
 403                     Private->Cpu,
 404                     TimerVector,
 405                     NULL
 406                     );
 407     SetPitCount (0);
 408
 409     //
 410     // Save status that the Timer AP is not using the 8254 PIT
 411     //
 412     Private->TimerUses8254 = FALSE;
 413   } else if (Status == EFI_ALREADY_STARTED) {
 414     //
 415     // Save status that the Timer AP is using the 8254 PIT
 416     //
 417     Private->TimerUses8254 = TRUE;
 418   } else {
 419     //
 420     // Unexpected status from CPU AP RegisterInterruptHandler()
 421     //
 422     ASSERT (FALSE);
 423   }
 424
 425   return EFI_SUCCESS;
 426 }