QuarkPlatformPkg/Acpi/Dxe/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) 2013-2015 Intel Corporation.
   7
   8 SPDX-License-Identifier: BSD-2-Clause-Patent
   9
  10 **/
  11 #include "ScriptExecute.h"
  12 //
  13 // INTERRUPT_GATE_DESCRIPTOR and SetIdtEntry () are used to setup IDT to do debug
  14 //
  15
  16 #pragma pack(1)
  17
  18 typedef struct {
  19   UINT16  OffsetLow;
  20   UINT16  SegmentSelector;
  21   UINT16  Attributes;
  22   UINT16  OffsetHigh;
  23 } INTERRUPT_GATE_DESCRIPTOR;
  24
  25 #define INTERRUPT_GATE_ATTRIBUTE   0x8e00
  26
  27 #pragma pack()
  28 /**
  29   Set a IDT entry for interrupt vector 3 for debug purpose.
  30
  31   @param  AcpiS3Context  a pointer to a structure of ACPI_S3_CONTEXT
  32
  33 **/
  34 VOID
  35 SetIdtEntry (
  36   IN ACPI_S3_CONTEXT     *AcpiS3Context
  37   )
  38 {
  39   INTERRUPT_GATE_DESCRIPTOR                     *IdtEntry;
  40   IA32_DESCRIPTOR                               *IdtDescriptor;
  41   UINTN                                         S3DebugBuffer;
  42
  43   //
  44   // Restore IDT for debug
  45   //
  46   IdtDescriptor = (IA32_DESCRIPTOR *) (UINTN) (AcpiS3Context->IdtrProfile);
  47   IdtEntry = (INTERRUPT_GATE_DESCRIPTOR *)(IdtDescriptor->Base + (3 * sizeof (INTERRUPT_GATE_DESCRIPTOR)));
  48   S3DebugBuffer = (UINTN) (AcpiS3Context->S3DebugBufferAddress);
  49
  50   IdtEntry->OffsetLow       = (UINT16)S3DebugBuffer;
  51   IdtEntry->SegmentSelector = (UINT16)AsmReadCs ();
  52   IdtEntry->Attributes      = (UINT16)INTERRUPT_GATE_ATTRIBUTE;
  53   IdtEntry->OffsetHigh      = (UINT16)(S3DebugBuffer >> 16);
  54
  55   AsmWriteIdtr (IdtDescriptor);
  56 }
  57