MdePkg/Library/PeiServicesTablePointerLibIdt/PeiServicesTablePointer.c

   1 /** @file
   2   PEI Services Table Pointer Library for IA-32 and X64.
   3
   4   Copyright (c) 2006 - 2007, Intel Corporation.<BR>
   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 "InternalPeiServicesTablePointer.h"
  16
  17 /**
  18
  19   The function returns the pointer to PeiServicee following
  20   PI1.0.
  21
  22   For IA32, the four-bytes field immediately prior to new IDT
  23   base addres is used to save the EFI_PEI_SERVICES**.
  24   For x64, the eight-bytes field immediately prior to new IDT
  25   base addres is used to save the EFI_PEI_SERVICES**
  26
  27   @return  The pointer to PeiServices.
  28
  29 **/
  30 EFI_PEI_SERVICES **
  31 EFIAPI
  32 GetPeiServicesTablePointer (
  33   VOID
  34   )
  35 {
  36   EFI_PEI_SERVICES  **PeiServices;
  37   IA32_DESCRIPTOR   Idtr;
  38
  39   AsmReadIdtr (&Idtr);
  40   PeiServices = (EFI_PEI_SERVICES **) (*(UINTN*)(Idtr.Base - 4));
  41   ASSERT (PeiServices != NULL);
  42   return PeiServices;
  43 }
  44
  45 /**
  46
  47   The function sets the pointer to PeiServicee following
  48   PI1.0.
  49
  50   For IA32, the four-bytes field immediately prior to new IDT
  51   base addres is used to save the EFI_PEI_SERVICES**.
  52   For x64, the eight-bytes field immediately prior to new IDT
  53   base addres is used to save the EFI_PEI_SERVICES**
  54
  55   @param PeiServicesTablePointer  The pointer to PeiServices.
  56
  57 **/
  58 VOID
  59 EFIAPI
  60 SetPeiServicesTablePointer (
  61   EFI_PEI_SERVICES ** PeiServicesTablePointer
  62   )
  63 {
  64   IA32_DESCRIPTOR   Idtr;
  65
  66   AsmReadIdtr (&Idtr);
  67   (*(UINTN*)(Idtr.Base - 4)) = (UINTN)PeiServicesTablePointer;
  68 }
  69
  70 /**
  71   After memory initialization in PEI phase, the IDT table in temporary memory should
  72   be migrated to memory, and the address of PeiServicesPointer also need to be updated
  73   immediately preceding the new IDT table.
  74
  75   @param    PeiServices   The address of PeiServices pointer.
  76 **/
  77 VOID
  78 EFIAPI
  79 MigrateIdtTable (
  80   IN EFI_PEI_SERVICES  **PeiServices
  81   )
  82 {
  83   UINTN           Size;
  84   VOID            *NewBase;
  85   EFI_STATUS      Status;
  86   IA32_DESCRIPTOR Idtr;
  87
  88   AsmReadIdtr (&Idtr);
  89
  90   Size = sizeof(UINTN) + (Idtr.Limit + 1);
  91
  92   Status = PeiServicesAllocatePool (Size, &NewBase);
  93   ASSERT_EFI_ERROR (Status);
  94
  95   CopyMem ((VOID*)((UINTN)NewBase + sizeof(UINTN)), (VOID*)Idtr.Base, (Idtr.Limit + 1));
  96
  97   Idtr.Base = (UINTN)NewBase + sizeof(UINTN);
  98   AsmWriteIdtr (&Idtr);
  99   SetPeiServicesTablePointer(PeiServices);
 100 }
 101