MdeModulePkg/Universal/Acpi/BootScriptExecutorDxe/IA32/SetIdtEntry.c

   1 /** @file
   2   Set a IDT entry for debug purpose
   3
   4   Set a IDT entry for interrupt vector 3 for debug purpose for IA32 platform
   5
   6 Copyright (c) 2006 - 2013, Intel Corporation. All rights reserved.<BR>
   7
   8 This program and the accompanying materials
   9 are licensed and made available under the terms and conditions of the BSD License
  10 which accompanies this distribution.  The full text of the license may be found at
  11 http://opensource.org/licenses/bsd-license.php
  12
  13 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  14 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  15
  16 **/
  17 #include "ScriptExecute.h"
  18
  19 /**
  20   Set a IDT entry for interrupt vector 3 for debug purpose.
  21
  22   @param  AcpiS3Context  a pointer to a structure of ACPI_S3_CONTEXT
  23
  24 **/
  25 VOID
  26 SetIdtEntry (
  27   IN ACPI_S3_CONTEXT     *AcpiS3Context
  28   )
  29 {
  30   IA32_IDT_GATE_DESCRIPTOR                      *IdtEntry;
  31   IA32_DESCRIPTOR                               *IdtDescriptor;
  32   UINTN                                         S3DebugBuffer;
  33   EFI_STATUS                                    Status;
  34
  35   //
  36   // Restore IDT for debug
  37   //
  38   IdtDescriptor = (IA32_DESCRIPTOR *) (UINTN) (AcpiS3Context->IdtrProfile);
  39   AsmWriteIdtr (IdtDescriptor);
  40
  41   //
  42   // Setup the default CPU exception handlers
  43   //
  44   Status = InitializeCpuExceptionHandlers (NULL);
  45   ASSERT_EFI_ERROR (Status);
  46
  47   DEBUG_CODE (
  48     //
  49     // Update IDT entry INT3 if the instruction is valid in it
  50     //
  51     S3DebugBuffer = (UINTN) (AcpiS3Context->S3DebugBufferAddress);
  52     if (*(UINTN *)S3DebugBuffer != (UINTN) -1) {
  53       IdtEntry = (IA32_IDT_GATE_DESCRIPTOR *)(IdtDescriptor->Base + (3 * sizeof (IA32_IDT_GATE_DESCRIPTOR)));
  54       IdtEntry->Bits.OffsetLow      = (UINT16)S3DebugBuffer;
  55       IdtEntry->Bits.Selector       = (UINT16)AsmReadCs ();
  56       IdtEntry->Bits.Reserved_0     = 0;
  57       IdtEntry->Bits.GateType       = IA32_IDT_GATE_TYPE_INTERRUPT_32;
  58       IdtEntry->Bits.OffsetHigh     = (UINT16)(S3DebugBuffer >> 16);
  59     }
  60   );
  61 }
  62