MdeModulePkg/Universal/DebugSupportDxe/X64/PlDebugSupportX64.c

   1 /** @file
   2   X64 specific functions to support Debug Support protocol.
   3
   4 Copyright (c) 2008 - 2010, Intel Corporation. All rights reserved.<BR>
   5 SPDX-License-Identifier: BSD-2-Clause-Patent
   6
   7 **/
   8
   9 #include "PlDebugSupport.h"
  10
  11 IA32_IDT_GATE_DESCRIPTOR  NullDesc = {
  12   { 0, 0 }
  13 };
  14
  15 /**
  16   Get Interrupt Handle from IDT Gate Descriptor.
  17
  18   @param  IdtGateDecriptor  IDT Gate Descriptor.
  19
  20   @return Interrupt Handle stored in IDT Gate Descriptor.
  21
  22 **/
  23 UINTN
  24 GetInterruptHandleFromIdt (
  25   IN IA32_IDT_GATE_DESCRIPTOR  *IdtGateDecriptor
  26   )
  27 {
  28   UINTN  InterruptHandle;
  29
  30   //
  31   // InterruptHandle  0-15 : OffsetLow
  32   // InterruptHandle 16-31 : OffsetHigh
  33   // InterruptHandle 32-63 : OffsetUpper
  34   //
  35   InterruptHandle = ((UINTN)IdtGateDecriptor->Bits.OffsetLow) |
  36                     (((UINTN)IdtGateDecriptor->Bits.OffsetHigh)  << 16) |
  37                     (((UINTN)IdtGateDecriptor->Bits.OffsetUpper) << 32);
  38
  39   return InterruptHandle;
  40 }
  41
  42 /**
  43   Allocate pool for a new IDT entry stub.
  44
  45   Copy the generic stub into the new buffer and fixup the vector number
  46   and jump target address.
  47
  48   @param  ExceptionType   This is the exception type that the new stub will be created
  49                           for.
  50   @param  Stub            On successful exit, *Stub contains the newly allocated entry stub.
  51
  52 **/
  53 VOID
  54 CreateEntryStub (
  55   IN EFI_EXCEPTION_TYPE  ExceptionType,
  56   OUT VOID               **Stub
  57   )
  58 {
  59   UINT8  *StubCopy;
  60
  61   StubCopy = *Stub;
  62
  63   //
  64   // Fixup the stub code for this vector
  65   //
  66
  67   // The stub code looks like this:
  68   //
  69   //    00000000  6A 00               push    0                       ; push vector number - will be modified before installed
  70   //    00000002  E9                  db      0e9h                    ; jump rel32
  71   //    00000003  00000000            dd      0                       ; fixed up to relative address of CommonIdtEntry
  72   //
  73
  74   //
  75   // poke in the exception type so the second push pushes the exception type
  76   //
  77   StubCopy[0x1] = (UINT8)ExceptionType;
  78
  79   //
  80   // fixup the jump target to point to the common entry
  81   //
  82   *(UINT32 *)&StubCopy[0x3] = (UINT32)((UINTN)CommonIdtEntry - (UINTN)&StubCopy[StubSize]);
  83
  84   return;
  85 }
  86
  87 /**
  88   This is the main worker function that manages the state of the interrupt
  89   handlers.  It both installs and uninstalls interrupt handlers based on the
  90   value of NewCallback.  If NewCallback is NULL, then uninstall is indicated.
  91   If NewCallback is non-NULL, then install is indicated.
  92
  93   @param  NewCallback   If non-NULL, NewCallback specifies the new handler to register.
  94                         If NULL, specifies that the previously registered handler should
  95                         be uninstalled.
  96   @param  ExceptionType Indicates which entry to manage.
  97
  98   @retval EFI_SUCCESS            Process is ok.
  99   @retval EFI_INVALID_PARAMETER  Requested uninstalling a handler from a vector that has
 100                                  no handler registered for it
 101   @retval EFI_ALREADY_STARTED    Requested install to a vector that already has a handler registered.
 102   @retval others                 Possible return values are passed through from UnHookEntry and HookEntry.
 103
 104 **/
 105 EFI_STATUS
 106 ManageIdtEntryTable (
 107   CALLBACK_FUNC       NewCallback,
 108   EFI_EXCEPTION_TYPE  ExceptionType
 109   )
 110 {
 111   EFI_STATUS  Status;
 112
 113   Status = EFI_SUCCESS;
 114
 115   if (CompareMem (&IdtEntryTable[ExceptionType].NewDesc, &NullDesc, sizeof (IA32_IDT_GATE_DESCRIPTOR)) != 0) {
 116     //
 117     // we've already installed to this vector
 118     //
 119     if (NewCallback != NULL) {
 120       //
 121       // if the input handler is non-null, error
 122       //
 123       Status = EFI_ALREADY_STARTED;
 124     } else {
 125       UnhookEntry (ExceptionType);
 126     }
 127   } else {
 128     //
 129     // no user handler installed on this vector
 130     //
 131     if (NewCallback == NULL) {
 132       //
 133       // if the input handler is null, error
 134       //
 135       Status = EFI_INVALID_PARAMETER;
 136     } else {
 137       HookEntry (ExceptionType, NewCallback);
 138     }
 139   }
 140
 141   return Status;
 142 }