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 /**
  21   Caches a pointer PEI Services Table.
  22
  23   Caches the pointer to the PEI Services Table specified by PeiServicesTablePointer
  24   in a CPU specific manner as specified in the CPU binding section of the Platform Initialization
  25   Pre-EFI Initialization Core Interface Specification.
  26
  27   If PeiServicesTablePointer is NULL, then ASSERT().
  28
  29   @param    PeiServicesTablePointer   The address of PeiServices pointer.
  30 **/
  31 VOID
  32 EFIAPI
  33 SetPeiServicesTablePointer (
  34   IN CONST EFI_PEI_SERVICES ** PeiServicesTablePointer
  35   )
  36 {
  37   ASSERT (PeiServicesTablePointer != NULL);
  38   ASSERT (*PeiServicesTablePointer != NULL);
  39   EMU_MAGIC_PAGE()->PeiServicesTablePointer = PeiServicesTablePointer;
  40 }
  41
  42 /**
  43   Retrieves the cached value of the PEI Services Table pointer.
  44
  45   Returns the cached value of the PEI Services Table pointer in a CPU specific manner
  46   as specified in the CPU binding section of the Platform Initialization Pre-EFI
  47   Initialization Core Interface Specification.
  48
  49   If the cached PEI Services Table pointer is NULL, then ASSERT().
  50
  51   @return  The pointer to PeiServices.
  52
  53 **/
  54 CONST EFI_PEI_SERVICES **
  55 EFIAPI
  56 GetPeiServicesTablePointer (
  57   VOID
  58   )
  59 {
  60   CONST EFI_PEI_SERVICES **PeiServicesTablePointer;
  61
  62   PeiServicesTablePointer = EMU_MAGIC_PAGE()->PeiServicesTablePointer;
  63   ASSERT (PeiServicesTablePointer != NULL);
  64   ASSERT (*PeiServicesTablePointer != NULL);
  65   return PeiServicesTablePointer;
  66 }
  67
  68 /**
  69   Perform CPU specific actions required to migrate the PEI Services Table
  70   pointer from temporary RAM to permanent RAM.
  71
  72   For IA32 CPUs, the PEI Services Table pointer is stored in the 4 bytes
  73   immediately preceding the Interrupt Descriptor Table (IDT) in memory.
  74   For X64 CPUs, the PEI Services Table pointer is stored in the 8 bytes
  75   immediately preceding the Interrupt Descriptor Table (IDT) in memory.
  76   For Itanium and ARM CPUs, a the PEI Services Table Pointer is stored in
  77   a dedicated CPU register.  This means that there is no memory storage
  78   associated with storing the PEI Services Table pointer, so no additional
  79   migration actions are required for Itanium or ARM CPUs.
  80
  81 **/
  82 VOID
  83 EFIAPI
  84 MigratePeiServicesTablePointer (
  85   VOID
  86   )
  87 {
  88   //
  89   //  PEI Services Table pointer is cached in SRAM. No additional
  90   //  migration actions are required.
  91   //
  92   return;
  93 }
  94
  95