SourceLevelDebugPkg/Library/PeCoffExtraActionLibDebug/X64/IntHandlerFuncs.c

   1 /** @file
   2   X64 arch function to access IDT vector.
   3
   4   Copyright (c) 2013 - 2018, Intel Corporation. All rights reserved.<BR>
   5   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 <PeCoffExtraActionLib.h>
  16
  17 /**
  18   Read IDT entry to check if IDT entries are setup by Debug Agent.
  19
  20   @param[in]  IdtDescriptor      Pointer to IDT Descriptor.
  21   @param[in]  InterruptType      Interrupt type.
  22
  23   @retval  TRUE     IDT entries were setup by Debug Agent.
  24   @retval  FALSE    IDT entries were not setuo by Debug Agent.
  25
  26 **/
  27 BOOLEAN
  28 CheckDebugAgentHandler (
  29   IN  IA32_DESCRIPTOR            *IdtDescriptor,
  30   IN  UINTN                      InterruptType
  31   )
  32 {
  33   IA32_IDT_GATE_DESCRIPTOR   *IdtEntry;
  34   UINTN                      InterruptHandler;
  35
  36   IdtEntry = (IA32_IDT_GATE_DESCRIPTOR *) IdtDescriptor->Base;
  37   if (IdtEntry == NULL) {
  38     return FALSE;
  39   }
  40
  41   InterruptHandler = IdtEntry[InterruptType].Bits.OffsetLow +
  42                     (((UINTN)IdtEntry[InterruptType].Bits.OffsetHigh) << 16) +
  43                     (((UINTN)IdtEntry[InterruptType].Bits.OffsetUpper) << 32);
  44   if (InterruptHandler >= sizeof (UINT32) &&  *(UINT32 *)(InterruptHandler - sizeof (UINT32)) == AGENT_HANDLER_SIGNATURE) {
  45     return TRUE;
  46   } else {
  47     return FALSE;
  48   }
  49 }
  50
  51 /**
  52   Save IDT entry for INT1 and update it.
  53
  54   @param[in]  IdtDescriptor      Pointer to IDT Descriptor.
  55   @param[out] SavedIdtEntry      Original IDT entry returned.
  56
  57 **/
  58 VOID
  59 SaveAndUpdateIdtEntry1 (
  60   IN  IA32_DESCRIPTOR            *IdtDescriptor,
  61   OUT IA32_IDT_GATE_DESCRIPTOR   *SavedIdtEntry
  62   )
  63 {
  64   IA32_IDT_GATE_DESCRIPTOR   *IdtEntry;
  65   UINT16                     CodeSegment;
  66   UINTN                      InterruptHandler;
  67
  68   IdtEntry = (IA32_IDT_GATE_DESCRIPTOR *) IdtDescriptor->Base;
  69   CopyMem (SavedIdtEntry, &IdtEntry[1], sizeof (IA32_IDT_GATE_DESCRIPTOR));
  70
  71     //
  72   // Use current CS as the segment selector of interrupt gate in IDT
  73   //
  74   CodeSegment = AsmReadCs ();
  75
  76   InterruptHandler = (UINTN) &AsmInterruptHandle;
  77   IdtEntry[1].Bits.OffsetLow       = (UINT16)(UINTN)InterruptHandler;
  78   IdtEntry[1].Bits.OffsetHigh      = (UINT16)((UINTN)InterruptHandler >> 16);
  79   IdtEntry[1].Bits.OffsetUpper     = (UINT32)((UINTN)InterruptHandler >> 32);
  80   IdtEntry[1].Bits.Selector        = CodeSegment;
  81   IdtEntry[1].Bits.GateType        = IA32_IDT_GATE_TYPE_INTERRUPT_32;
  82 }
  83
  84 /**
  85   Restore IDT entry for INT1.
  86
  87   @param[in]  IdtDescriptor      Pointer to IDT Descriptor.
  88   @param[in]  RestoredIdtEntry   IDT entry to be restored.
  89
  90 **/
  91 VOID
  92 RestoreIdtEntry1 (
  93   IN  IA32_DESCRIPTOR            *IdtDescriptor,
  94   IN  IA32_IDT_GATE_DESCRIPTOR   *RestoredIdtEntry
  95   )
  96 {
  97   IA32_IDT_GATE_DESCRIPTOR   *IdtEntry;
  98
  99   IdtEntry = (IA32_IDT_GATE_DESCRIPTOR *) IdtDescriptor->Base;
 100   CopyMem (&IdtEntry[1], RestoredIdtEntry, sizeof (IA32_IDT_GATE_DESCRIPTOR));
 101 }