EmulatorPkg/Library/PeiServicesTablePointerLibMagicPage/PeiServicesTablePointer.c

   1 /** @file
   2   PEI Services Table Pointer Library.
   3
   4   Store PEI Services Table pointer via gEmulatorPkgTokenSpaceGuid.PcdPeiServicesTablePage.
   5   This emulates a platform SRAM. The PI mechaism does not work in the emulator due to
   6   lack of privledge.
   7
   8   Copyright (c) 2006 - 2010, Intel Corporation. All rights reserved.<BR>
   9   Portiions copyrigth (c) 2011, Apple Inc. All rights reserved.
  10   SPDX-License-Identifier: BSD-2-Clause-Patent
  11
  12 **/
  13
  14 #include <PiPei.h>
  15 #include <Library/PeiServicesTablePointerLib.h>
  16 #include <Library/DebugLib.h>
  17 #include <Library/EmuMagicPageLib.h>
  18
  19 /**
  20   Caches a pointer PEI Services Table.
  21
  22   Caches the pointer to the PEI Services Table specified by PeiServicesTablePointer
  23   in a CPU specific manner as specified in the CPU binding section of the Platform Initialization
  24   Pre-EFI Initialization Core Interface Specification.
  25
  26   If PeiServicesTablePointer is NULL, then ASSERT().
  27
  28   @param    PeiServicesTablePointer   The address of PeiServices pointer.
  29 **/
  30 VOID
  31 EFIAPI
  32 SetPeiServicesTablePointer (
  33   IN CONST EFI_PEI_SERVICES  **PeiServicesTablePointer
  34   )
  35 {
  36   ASSERT (PeiServicesTablePointer != NULL);
  37   ASSERT (*PeiServicesTablePointer != NULL);
  38   EMU_MAGIC_PAGE ()->PeiServicesTablePointer = PeiServicesTablePointer;
  39 }
  40
  41 /**
  42   Retrieves the cached value of the PEI Services Table pointer.
  43
  44   Returns the cached value of the PEI Services Table pointer in a CPU specific manner
  45   as specified in the CPU binding section of the Platform Initialization Pre-EFI
  46   Initialization Core Interface Specification.
  47
  48   If the cached PEI Services Table pointer is NULL, then ASSERT().
  49
  50   @return  The pointer to PeiServices.
  51
  52 **/
  53 CONST EFI_PEI_SERVICES **
  54 EFIAPI
  55 GetPeiServicesTablePointer (
  56   VOID
  57   )
  58 {
  59   CONST EFI_PEI_SERVICES  **PeiServicesTablePointer;
  60
  61   PeiServicesTablePointer = EMU_MAGIC_PAGE ()->PeiServicesTablePointer;
  62   ASSERT (PeiServicesTablePointer != NULL);
  63   ASSERT (*PeiServicesTablePointer != NULL);
  64   return PeiServicesTablePointer;
  65 }
  66
  67 /**
  68   Perform CPU specific actions required to migrate the PEI Services Table
  69   pointer from temporary RAM to permanent RAM.
  70
  71   For IA32 CPUs, the PEI Services Table pointer is stored in the 4 bytes
  72   immediately preceding the Interrupt Descriptor Table (IDT) in memory.
  73   For X64 CPUs, the PEI Services Table pointer is stored in the 8 bytes
  74   immediately preceding the Interrupt Descriptor Table (IDT) in memory.
  75   For Itanium and ARM CPUs, a the PEI Services Table Pointer is stored in
  76   a dedicated CPU register.  This means that there is no memory storage
  77   associated with storing the PEI Services Table pointer, so no additional
  78   migration actions are required for Itanium or ARM CPUs.
  79
  80 **/
  81 VOID
  82 EFIAPI
  83 MigratePeiServicesTablePointer (
  84   VOID
  85   )
  86 {
  87   //
  88   //  PEI Services Table pointer is cached in SRAM. No additional
  89   //  migration actions are required.
  90   //
  91   return;
  92 }