system76-edk2/UefiCpuPkg/Library/CpuExceptionHandlerLib/Ia32/ArchExceptionHandler.c

/** @file
  IA32 CPU Exception Handler functons.

  Copyright (c) 2012 - 2017, Intel Corporation. All rights reserved.<BR>
  This program and the accompanying materials
  are licensed and made available under the terms and conditions of the BSD License
  which accompanies this distribution.  The full text of the license may be found at
  http://opensource.org/licenses/bsd-license.php

  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.

**/

#include "CpuExceptionCommon.h"

/**
  Return address map of exception handler template so that C code can generate
  exception tables.

  @param IdtEntry          Pointer to IDT entry to be updated.
  @param InterruptHandler  IDT handler value.

**/
VOID
ArchUpdateIdtEntry (
  IN IA32_IDT_GATE_DESCRIPTOR        *IdtEntry,
  IN UINTN                           InterruptHandler
  )
{
  IdtEntry->Bits.OffsetLow   = (UINT16)(UINTN)InterruptHandler;
  IdtEntry->Bits.OffsetHigh  = (UINT16)((UINTN)InterruptHandler >> 16);
  IdtEntry->Bits.GateType    = IA32_IDT_GATE_TYPE_INTERRUPT_32;
}

/**
  Read IDT handler value from IDT entry.

  @param IdtEntry          Pointer to IDT entry to be read.

**/
UINTN
ArchGetIdtHandler (
  IN IA32_IDT_GATE_DESCRIPTOR        *IdtEntry
  )
{
  return (UINTN)IdtEntry->Bits.OffsetLow + (((UINTN)IdtEntry->Bits.OffsetHigh) << 16);
}

/**
  Save CPU exception context when handling EFI_VECTOR_HANDOFF_HOOK_AFTER case.

  @param[in] ExceptionType        Exception type.
  @param[in] SystemContext        Pointer to EFI_SYSTEM_CONTEXT.
  @param[in] ExceptionHandlerData Pointer to exception handler data.
**/
VOID
ArchSaveExceptionContext (
  IN UINTN                        ExceptionType,
  IN EFI_SYSTEM_CONTEXT           SystemContext,
  IN EXCEPTION_HANDLER_DATA       *ExceptionHandlerData
  )
{
  IA32_EFLAGS32           Eflags;
  RESERVED_VECTORS_DATA   *ReservedVectors;

  ReservedVectors = ExceptionHandlerData->ReservedVectors;
  //
  // Save Exception context in global variable
  //
  ReservedVectors[ExceptionType].OldFlags      = SystemContext.SystemContextIa32->Eflags;
  ReservedVectors[ExceptionType].OldCs         = SystemContext.SystemContextIa32->Cs;
  ReservedVectors[ExceptionType].OldIp         = SystemContext.SystemContextIa32->Eip;
  ReservedVectors[ExceptionType].ExceptionData = SystemContext.SystemContextIa32->ExceptionData;
  //
  // Clear IF flag to avoid old IDT handler enable interrupt by IRET
  //
  Eflags.UintN = SystemContext.SystemContextIa32->Eflags;
  Eflags.Bits.IF = 0;
  SystemContext.SystemContextIa32->Eflags = Eflags.UintN;
  //
  // Modify the EIP in stack, then old IDT handler will return to the stub code
  //
  SystemContext.SystemContextIa32->Eip    = (UINTN) ReservedVectors[ExceptionType].HookAfterStubHeaderCode;
}

/**
  Restore CPU exception context when handling EFI_VECTOR_HANDOFF_HOOK_AFTER case.

  @param[in] ExceptionType        Exception type.
  @param[in] SystemContext        Pointer to EFI_SYSTEM_CONTEXT.
  @param[in] ExceptionHandlerData Pointer to exception handler data.
**/
VOID
ArchRestoreExceptionContext (
  IN UINTN                        ExceptionType,
  IN EFI_SYSTEM_CONTEXT           SystemContext,
  IN EXCEPTION_HANDLER_DATA       *ExceptionHandlerData
  )
{
  RESERVED_VECTORS_DATA   *ReservedVectors;

  ReservedVectors = ExceptionHandlerData->ReservedVectors;
  SystemContext.SystemContextIa32->Eflags        = ReservedVectors[ExceptionType].OldFlags;
  SystemContext.SystemContextIa32->Cs            = ReservedVectors[ExceptionType].OldCs;
  SystemContext.SystemContextIa32->Eip           = ReservedVectors[ExceptionType].OldIp;
  SystemContext.SystemContextIa32->ExceptionData = ReservedVectors[ExceptionType].ExceptionData;
}

/**
  Setup separate stack for given exceptions.

  @param[in] StackSwitchData      Pointer to data required for setuping up
                                  stack switch.

  @retval EFI_SUCCESS             The exceptions have been successfully
                                  initialized with new stack.
  @retval EFI_INVALID_PARAMETER   StackSwitchData contains invalid content.

**/
EFI_STATUS
ArchSetupExcpetionStack (
  IN CPU_EXCEPTION_INIT_DATA      *StackSwitchData
  )
{
  IA32_DESCRIPTOR                   Gdtr;
  IA32_DESCRIPTOR                   Idtr;
  IA32_IDT_GATE_DESCRIPTOR          *IdtTable;
  IA32_TSS_DESCRIPTOR               *TssDesc;
  IA32_TASK_STATE_SEGMENT           *Tss;
  UINTN                             StackTop;
  UINTN                             Index;
  UINTN                             Vector;
  UINTN                             TssBase;
  UINTN                             GdtSize;
  EXCEPTION_HANDLER_TEMPLATE_MAP    TemplateMap;

  if (StackSwitchData == NULL ||
      StackSwitchData->Ia32.Revision != CPU_EXCEPTION_INIT_DATA_REV ||
      StackSwitchData->Ia32.KnownGoodStackTop == 0 ||
      StackSwitchData->Ia32.KnownGoodStackSize == 0 ||
      StackSwitchData->Ia32.StackSwitchExceptions == NULL ||
      StackSwitchData->Ia32.StackSwitchExceptionNumber == 0 ||
      StackSwitchData->Ia32.StackSwitchExceptionNumber > CPU_EXCEPTION_NUM ||
      StackSwitchData->Ia32.GdtTable == NULL ||
      StackSwitchData->Ia32.IdtTable == NULL ||
      StackSwitchData->Ia32.ExceptionTssDesc == NULL ||
      StackSwitchData->Ia32.ExceptionTss == NULL) {
    return EFI_INVALID_PARAMETER;
  }

  //
  // The caller is responsible for that the GDT table, no matter the existing
  // one or newly allocated, has enough space to hold descriptors for exception
  // task-state segments.
  //
  if (((UINTN)StackSwitchData->Ia32.GdtTable & (IA32_GDT_ALIGNMENT - 1)) != 0) {
    return EFI_INVALID_PARAMETER;
  }

  if ((UINTN)StackSwitchData->Ia32.ExceptionTssDesc < (UINTN)(StackSwitchData->Ia32.GdtTable)) {
    return EFI_INVALID_PARAMETER;
  }

  if ((UINTN)StackSwitchData->Ia32.ExceptionTssDesc + StackSwitchData->Ia32.ExceptionTssDescSize >
      ((UINTN)(StackSwitchData->Ia32.GdtTable) + StackSwitchData->Ia32.GdtTableSize)) {
    return EFI_INVALID_PARAMETER;
  }

  //
  // We need one descriptor and one TSS for current task and every exception
  // specified.
  //
  if (StackSwitchData->Ia32.ExceptionTssDescSize <
      sizeof (IA32_TSS_DESCRIPTOR) * (StackSwitchData->Ia32.StackSwitchExceptionNumber + 1)) {
    return EFI_INVALID_PARAMETER;
  }
  if (StackSwitchData->Ia32.ExceptionTssSize <
      sizeof (IA32_TASK_STATE_SEGMENT) * (StackSwitchData->Ia32.StackSwitchExceptionNumber + 1)) {
    return EFI_INVALID_PARAMETER;
  }

  TssDesc = StackSwitchData->Ia32.ExceptionTssDesc;
  Tss     = StackSwitchData->Ia32.ExceptionTss;

  //
  // Initialize new GDT table and/or IDT table, if any
  //
  AsmReadIdtr (&Idtr);
  AsmReadGdtr (&Gdtr);

  GdtSize = (UINTN)TssDesc +
            sizeof (IA32_TSS_DESCRIPTOR) *
            (StackSwitchData->Ia32.StackSwitchExceptionNumber + 1) -
            (UINTN)(StackSwitchData->Ia32.GdtTable);
  if ((UINTN)StackSwitchData->Ia32.GdtTable != Gdtr.Base) {
    CopyMem (StackSwitchData->Ia32.GdtTable, (VOID *)Gdtr.Base, Gdtr.Limit + 1);
    Gdtr.Base = (UINTN)StackSwitchData->Ia32.GdtTable;
    Gdtr.Limit = (UINT16)GdtSize - 1;
  }

  if ((UINTN)StackSwitchData->Ia32.IdtTable != Idtr.Base) {
    Idtr.Base = (UINTN)StackSwitchData->Ia32.IdtTable;
  }
  if (StackSwitchData->Ia32.IdtTableSize > 0) {
    Idtr.Limit = (UINT16)(StackSwitchData->Ia32.IdtTableSize - 1);
  }

  //
  // Fixup current task descriptor. Task-state segment for current task will
  // be filled by processor during task switching.
  //
  TssBase = (UINTN)Tss;

  TssDesc->Bits.LimitLow   = sizeof(IA32_TASK_STATE_SEGMENT) - 1;
  TssDesc->Bits.BaseLow    = (UINT16)TssBase;
  TssDesc->Bits.BaseMid    = (UINT8)(TssBase >> 16);
  TssDesc->Bits.Type       = IA32_GDT_TYPE_TSS;
  TssDesc->Bits.P          = 1;
  TssDesc->Bits.LimitHigh  = 0;
  TssDesc->Bits.BaseHigh   = (UINT8)(TssBase >> 24);

  //
  // Fixup exception task descriptor and task-state segment
  //
  AsmGetTssTemplateMap (&TemplateMap);
  StackTop = StackSwitchData->Ia32.KnownGoodStackTop - CPU_STACK_ALIGNMENT;
  StackTop = (UINTN)ALIGN_POINTER (StackTop, CPU_STACK_ALIGNMENT);
  IdtTable = StackSwitchData->Ia32.IdtTable;
  for (Index = 0; Index < StackSwitchData->Ia32.StackSwitchExceptionNumber; ++Index) {
    TssDesc += 1;
    Tss     += 1;

    //
    // Fixup TSS descriptor
    //
    TssBase = (UINTN)Tss;

    TssDesc->Bits.LimitLow  = sizeof(IA32_TASK_STATE_SEGMENT) - 1;
    TssDesc->Bits.BaseLow   = (UINT16)TssBase;
    TssDesc->Bits.BaseMid   = (UINT8)(TssBase >> 16);
    TssDesc->Bits.Type      = IA32_GDT_TYPE_TSS;
    TssDesc->Bits.P         = 1;
    TssDesc->Bits.LimitHigh = 0;
    TssDesc->Bits.BaseHigh  = (UINT8)(TssBase >> 24);

    //
    // Fixup TSS
    //
    Vector = StackSwitchData->Ia32.StackSwitchExceptions[Index];
    if (Vector >= CPU_EXCEPTION_NUM ||
        Vector >= (Idtr.Limit + 1) / sizeof (IA32_IDT_GATE_DESCRIPTOR)) {
      continue;
    }

    Tss->EIP    = (UINT32)(TemplateMap.ExceptionStart
                           + Vector * TemplateMap.ExceptionStubHeaderSize);
    Tss->EFLAGS = 0x2;
    Tss->ESP    = StackTop;
    Tss->CR3    = AsmReadCr3 ();
    Tss->ES     = AsmReadEs ();
    Tss->CS     = AsmReadCs ();
    Tss->SS     = AsmReadSs ();
    Tss->DS     = AsmReadDs ();
    Tss->FS     = AsmReadFs ();
    Tss->GS     = AsmReadGs ();

    StackTop   -= StackSwitchData->Ia32.KnownGoodStackSize;

    //
    // Update IDT to use Task Gate for given exception
    //
    IdtTable[Vector].Bits.OffsetLow  = 0;
    IdtTable[Vector].Bits.Selector   = (UINT16)((UINTN)TssDesc - Gdtr.Base);
    IdtTable[Vector].Bits.Reserved_0 = 0;
    IdtTable[Vector].Bits.GateType   = IA32_IDT_GATE_TYPE_TASK;
    IdtTable[Vector].Bits.OffsetHigh = 0;
  }

  //
  // Publish GDT
  //
  AsmWriteGdtr (&Gdtr);

  //
  // Load current task
  //
  AsmWriteTr ((UINT16)((UINTN)StackSwitchData->Ia32.ExceptionTssDesc - Gdtr.Base));

  //
  // Publish IDT
  //
  AsmWriteIdtr (&Idtr);

  return EFI_SUCCESS;
}

/**
  Display processor context.

  @param[in] ExceptionType  Exception type.
  @param[in] SystemContext  Processor context to be display.
**/
VOID
EFIAPI
DumpCpuContext (
  IN EFI_EXCEPTION_TYPE   ExceptionType,
  IN EFI_SYSTEM_CONTEXT   SystemContext
  )
{
  InternalPrintMessage (
    "!!!! IA32 Exception Type - %02x(%a)  CPU Apic ID - %08x !!!!\n",
    ExceptionType,
    GetExceptionNameStr (ExceptionType),
    GetApicId ()
    );
  if ((mErrorCodeFlag & (1 << ExceptionType)) != 0) {
    InternalPrintMessage (
      "ExceptionData - %08x",
      SystemContext.SystemContextIa32->ExceptionData
      );
    if (ExceptionType == EXCEPT_IA32_PAGE_FAULT) {
      InternalPrintMessage (
        "  I:%x R:%x U:%x W:%x P:%x PK:%x S:%x",
        (SystemContext.SystemContextIa32->ExceptionData & IA32_PF_EC_ID)   != 0,
        (SystemContext.SystemContextIa32->ExceptionData & IA32_PF_EC_RSVD) != 0,
        (SystemContext.SystemContextIa32->ExceptionData & IA32_PF_EC_US)   != 0,
        (SystemContext.SystemContextIa32->ExceptionData & IA32_PF_EC_WR)   != 0,
        (SystemContext.SystemContextIa32->ExceptionData & IA32_PF_EC_P)    != 0,
        (SystemContext.SystemContextIa32->ExceptionData & IA32_PF_EC_PK)   != 0,
        (SystemContext.SystemContextIa32->ExceptionData & IA32_PF_EC_SGX)  != 0
        );
    }
    InternalPrintMessage ("\n");
  }
  InternalPrintMessage (
    "EIP  - %08x, CS  - %08x, EFLAGS - %08x\n",
    SystemContext.SystemContextIa32->Eip,
    SystemContext.SystemContextIa32->Cs,
    SystemContext.SystemContextIa32->Eflags
    );
  InternalPrintMessage (
    "EAX  - %08x, ECX - %08x, EDX - %08x, EBX - %08x\n",
    SystemContext.SystemContextIa32->Eax,
    SystemContext.SystemContextIa32->Ecx,
    SystemContext.SystemContextIa32->Edx,
    SystemContext.SystemContextIa32->Ebx
    );
  InternalPrintMessage (
    "ESP  - %08x, EBP - %08x, ESI - %08x, EDI - %08x\n",
    SystemContext.SystemContextIa32->Esp,
    SystemContext.SystemContextIa32->Ebp,
    SystemContext.SystemContextIa32->Esi,
    SystemContext.SystemContextIa32->Edi
    );
  InternalPrintMessage (
    "DS   - %08x, ES  - %08x, FS  - %08x, GS  - %08x, SS - %08x\n",
    SystemContext.SystemContextIa32->Ds,
    SystemContext.SystemContextIa32->Es,
    SystemContext.SystemContextIa32->Fs,
    SystemContext.SystemContextIa32->Gs,
    SystemContext.SystemContextIa32->Ss
    );
  InternalPrintMessage (
    "CR0  - %08x, CR2 - %08x, CR3 - %08x, CR4 - %08x\n",
    SystemContext.SystemContextIa32->Cr0,
    SystemContext.SystemContextIa32->Cr2,
    SystemContext.SystemContextIa32->Cr3,
    SystemContext.SystemContextIa32->Cr4
    );
  InternalPrintMessage (
    "DR0  - %08x, DR1 - %08x, DR2 - %08x, DR3 - %08x\n",
    SystemContext.SystemContextIa32->Dr0,
    SystemContext.SystemContextIa32->Dr1,
    SystemContext.SystemContextIa32->Dr2,
    SystemContext.SystemContextIa32->Dr3
    );
  InternalPrintMessage (
    "DR6  - %08x, DR7 - %08x\n",
    SystemContext.SystemContextIa32->Dr6,
    SystemContext.SystemContextIa32->Dr7
    );
  InternalPrintMessage (
    "GDTR - %08x %08x, IDTR - %08x %08x\n",
    SystemContext.SystemContextIa32->Gdtr[0],
    SystemContext.SystemContextIa32->Gdtr[1],
    SystemContext.SystemContextIa32->Idtr[0],
    SystemContext.SystemContextIa32->Idtr[1]
    );
  InternalPrintMessage (
    "LDTR - %08x, TR - %08x\n",
    SystemContext.SystemContextIa32->Ldtr,
    SystemContext.SystemContextIa32->Tr
    );
  InternalPrintMessage (
    "FXSAVE_STATE - %08x\n",
    &SystemContext.SystemContextIa32->FxSaveState
    );
}

/**
  Display CPU information.

  @param ExceptionType  Exception type.
  @param SystemContext  Pointer to EFI_SYSTEM_CONTEXT.
**/
VOID
DumpImageAndCpuContent (
  IN EFI_EXCEPTION_TYPE   ExceptionType,
  IN EFI_SYSTEM_CONTEXT   SystemContext
  )
{
  DumpCpuContext (ExceptionType, SystemContext);
  //
  // Dump module image base and module entry point by EIP
  //
  if ((ExceptionType == EXCEPT_IA32_PAGE_FAULT) &&
      ((SystemContext.SystemContextIa32->ExceptionData & IA32_PF_EC_ID) != 0)) {
    //
    // The EIP in SystemContext could not be used
    // if it is page fault with I/D set.
    //
    DumpModuleImageInfo ((*(UINTN *)(UINTN)SystemContext.SystemContextIa32->Esp));
  } else {
    DumpModuleImageInfo (SystemContext.SystemContextIa32->Eip);
  }
}