SourceLevelDebugPkg/Library/DebugAgent/DebugAgentCommon/X64/ArchDebugSupport.c

   1 /** @file
   2   Supporting functions for X64 architecture.
   3
   4   Copyright (c) 2010 - 2013, 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 "DebugAgent.h"
  16
  17 /**
  18   Initialize IDT entries to support source level debug.
  19
  20 **/
  21 VOID
  22 InitializeDebugIdt (
  23   VOID
  24   )
  25 {
  26   IA32_IDT_GATE_DESCRIPTOR   *IdtEntry;
  27   UINTN                      InterruptHandler;
  28   IA32_DESCRIPTOR            IdtDescriptor;
  29   UINTN                      Index;
  30   UINT16                     CodeSegment;
  31
  32   AsmReadIdtr (&IdtDescriptor);
  33
  34   //
  35   // Use current CS as the segment selector of interrupt gate in IDT
  36   //
  37   CodeSegment = AsmReadCs ();
  38
  39   IdtEntry = (IA32_IDT_GATE_DESCRIPTOR *) IdtDescriptor.Base;
  40
  41   for (Index = 0; Index < 20; Index ++) {
  42     if (((PcdGet32 (PcdExceptionsIgnoredByDebugger) & ~(BIT1 | BIT3)) & (1 << Index)) != 0) {
  43       //
  44       // If the exception is masked to be reserved except for INT1 and INT3, skip it
  45       //
  46       continue;
  47     }
  48     InterruptHandler = (UINTN)&Exception0Handle + Index * ExceptionStubHeaderSize;
  49     IdtEntry[Index].Bits.OffsetLow       = (UINT16)(UINTN)InterruptHandler;
  50     IdtEntry[Index].Bits.OffsetHigh      = (UINT16)((UINTN)InterruptHandler >> 16);
  51     IdtEntry[Index].Bits.OffsetUpper     = (UINT32)((UINTN)InterruptHandler >> 32);
  52     IdtEntry[Index].Bits.Selector        = CodeSegment;
  53     IdtEntry[Index].Bits.GateType        = IA32_IDT_GATE_TYPE_INTERRUPT_32;
  54   }
  55
  56   InterruptHandler = (UINTN) &TimerInterruptHandle;
  57   IdtEntry[DEBUG_TIMER_VECTOR].Bits.OffsetLow       = (UINT16)(UINTN)InterruptHandler;
  58   IdtEntry[DEBUG_TIMER_VECTOR].Bits.OffsetHigh      = (UINT16)((UINTN)InterruptHandler >> 16);
  59   IdtEntry[DEBUG_TIMER_VECTOR].Bits.OffsetUpper     = (UINT32)((UINTN)InterruptHandler >> 32);
  60   IdtEntry[DEBUG_TIMER_VECTOR].Bits.Selector        = CodeSegment;
  61   IdtEntry[DEBUG_TIMER_VECTOR].Bits.GateType        = IA32_IDT_GATE_TYPE_INTERRUPT_32;
  62
  63   //
  64   // Set DE flag in CR4 to enable IO breakpoint
  65   //
  66   AsmWriteCr4 (AsmReadCr4 () | BIT3);
  67 }
  68
  69 /**
  70   Retrieve exception handler from IDT table by ExceptionNum.
  71
  72   @param[in]  ExceptionNum    Exception number
  73
  74   @return Exception handler
  75
  76 **/
  77 VOID *
  78 GetExceptionHandlerInIdtEntry (
  79   IN UINTN             ExceptionNum
  80   )
  81 {
  82   IA32_IDT_GATE_DESCRIPTOR   *IdtEntry;
  83   IA32_DESCRIPTOR            IdtDescriptor;
  84
  85   AsmReadIdtr (&IdtDescriptor);
  86   IdtEntry = (IA32_IDT_GATE_DESCRIPTOR *) IdtDescriptor.Base;
  87
  88   return (VOID *) (IdtEntry[ExceptionNum].Bits.OffsetLow |
  89                   (((UINTN)IdtEntry[ExceptionNum].Bits.OffsetHigh) << 16) |
  90                   (((UINTN)IdtEntry[ExceptionNum].Bits.OffsetUpper) << 32));
  91 }
  92
  93 /**
  94   Set exception handler in IDT table by ExceptionNum.
  95
  96   @param[in]  ExceptionNum      Exception number
  97   @param[in]  ExceptionHandler  Exception Handler to be set
  98
  99 **/
 100 VOID
 101 SetExceptionHandlerInIdtEntry (
 102   IN UINTN             ExceptionNum,
 103   IN VOID              *ExceptionHandler
 104   )
 105 {
 106   IA32_IDT_GATE_DESCRIPTOR   *IdtEntry;
 107   IA32_DESCRIPTOR            IdtDescriptor;
 108
 109   AsmReadIdtr (&IdtDescriptor);
 110   IdtEntry = (IA32_IDT_GATE_DESCRIPTOR *) IdtDescriptor.Base;
 111
 112   IdtEntry[ExceptionNum].Bits.OffsetLow   = (UINT16)(UINTN)ExceptionHandler;
 113   IdtEntry[ExceptionNum].Bits.OffsetHigh  = (UINT16)((UINTN)ExceptionHandler >> 16);
 114   IdtEntry[ExceptionNum].Bits.OffsetUpper = (UINT32)((UINTN)ExceptionHandler >> 32);
 115 }