MdeModulePkg/Universal/DebugSupportDxe/X64/PlDebugSupportX64.c

   1 /** @file
   2   X64 specific debug support functions
   3
   4 Copyright (c) 2006 - 2007, Intel Corporation
   5 All rights reserved. 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 "DebugSupport.h"
  16
  17 /**
  18   Get Interrupt Handle from IDT Gate Descriptor.
  19
  20   @param  IdtGateDecriptor  IDT Gate Descriptor.
  21
  22   @return Interrupt Handle stored in IDT Gate Descriptor.
  23
  24 **/
  25 UINTN
  26 GetInterruptHandleFromIdt (
  27   IN IA32_IDT_GATE_DESCRIPTOR  *IdtGateDecriptor
  28   )
  29 {
  30   UINTN      InterruptHandle;
  31
  32   ((UINT16 *) &InterruptHandle)[0] = (UINT16) IdtGateDecriptor->Bits.OffsetLow;
  33   ((UINT16 *) &InterruptHandle)[1] = (UINT16) IdtGateDecriptor->Bits.OffsetHigh;
  34   ((UINT32 *) &InterruptHandle)[1] = (UINT32) IdtGateDecriptor->Bits.OffsetUpper;
  35
  36   return InterruptHandle;
  37 }
  38
  39 /**
  40   Allocate pool for a new IDT entry stub.
  41
  42   Copy the generic stub into the new buffer and fixup the vector number
  43   and jump target address.
  44
  45   @param  ExceptionType   This is the exception type that the new stub will be created
  46                           for.
  47   @param  Stub            On successful exit, *Stub contains the newly allocated entry stub.
  48
  49 **/
  50 VOID
  51 CreateEntryStub (
  52   IN EFI_EXCEPTION_TYPE     ExceptionType,
  53   OUT VOID                  **Stub
  54   )
  55 {
  56   UINT8       *StubCopy;
  57
  58   StubCopy = *Stub;
  59
  60   //
  61   // Fixup the stub code for this vector
  62   //
  63
  64   // The stub code looks like this:
  65   //
  66   //    00000000  6A 00               push    0                       ; push vector number - will be modified before installed
  67   //    00000002  E9                  db      0e9h                    ; jump rel32
  68   //    00000003  00000000            dd      0                       ; fixed up to relative address of CommonIdtEntry
  69   //
  70
  71   //
  72   // poke in the exception type so the second push pushes the exception type
  73   //
  74   StubCopy[0x1] = (UINT8) ExceptionType;
  75
  76   //
  77   // fixup the jump target to point to the common entry
  78   //
  79   *(UINT32 *) &StubCopy[0x3] = (UINT32)((UINTN) CommonIdtEntry - (UINTN) &StubCopy[StubSize]);
  80
  81   return;
  82 }
  83
  84 /**
  85   This is the main worker function that manages the state of the interrupt
  86   handlers.  It both installs and uninstalls interrupt handlers based on the
  87   value of NewCallback.  If NewCallback is NULL, then uninstall is indicated.
  88   If NewCallback is non-NULL, then install is indicated.
  89
  90   @param  NewCallback   If non-NULL, NewCallback specifies the new handler to register.
  91                         If NULL, specifies that the previously registered handler should
  92                         be uninstalled.
  93   @param  ExceptionType Indicates which entry to manage.
  94
  95   @retval EFI_SUCCESS            Process is ok.
  96   @retval EFI_INVALID_PARAMETER  Requested uninstalling a handler from a vector that has
  97                                  no handler registered for it
  98   @retval EFI_ALREADY_STARTED    Requested install to a vector that already has a handler registered.
  99   @retval others                 Possible return values are passed through from UnHookEntry and HookEntry.
 100
 101 **/
 102 EFI_STATUS
 103 ManageIdtEntryTable (
 104   VOID (*NewCallback)(),
 105   EFI_EXCEPTION_TYPE ExceptionType
 106   )
 107 {
 108   EFI_STATUS  Status;
 109
 110   Status = EFI_SUCCESS;
 111
 112   if (CompareMem (&IdtEntryTable[ExceptionType].NewDesc, &NullDesc, sizeof (IA32_IDT_GATE_DESCRIPTOR)) != 0) {
 113     //
 114     // we've already installed to this vector
 115     //
 116     if (NewCallback != NULL) {
 117       //
 118       // if the input handler is non-null, error
 119       //
 120       Status = EFI_ALREADY_STARTED;
 121     } else {
 122       UnhookEntry (ExceptionType);
 123     }
 124   } else {
 125     //
 126     // no user handler installed on this vector
 127     //
 128     if (NewCallback == NULL) {
 129       //
 130       // if the input handler is null, error
 131       //
 132       Status = EFI_INVALID_PARAMETER;
 133     } else {
 134       HookEntry (ExceptionType, NewCallback);
 135     }
 136   }
 137
 138   return Status;
 139 }