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