ArmPkg/Library/PeiServicesTablePointerLib/PeiServicesTablePointer.c

   1 /** @file
   2   PEI Services Table Pointer Library.
   3
   4   This library is used for PEIM which does executed from flash device directly but
   5   executed in memory.
   6
   7   Copyright (c) 2006 - 2010, Intel Corporation. All rights reserved.<BR>
   8   Copyright (c) 2011 Hewlett-Packard Corporation. All rights reserved.<BR>
   9   SPDX-License-Identifier: BSD-2-Clause-Patent
  10
  11 **/
  12
  13 #include <PiPei.h>
  14 #include <Library/PeiServicesTablePointerLib.h>
  15 #include <Library/ArmLib.h>
  16 #include <Library/DebugLib.h>
  17
  18 /**
  19   Caches a pointer PEI Services Table.
  20
  21   Caches the pointer to the PEI Services Table specified by PeiServicesTablePointer
  22   in a platform specific manner.
  23
  24   If PeiServicesTablePointer is NULL, then ASSERT().
  25
  26   @param    PeiServicesTablePointer   The address of PeiServices pointer.
  27 **/
  28 VOID
  29 EFIAPI
  30 SetPeiServicesTablePointer (
  31   IN CONST EFI_PEI_SERVICES ** PeiServicesTablePointer
  32   )
  33 {
  34   ArmWriteTpidrurw((UINTN)PeiServicesTablePointer);
  35 }
  36
  37 /**
  38   Retrieves the cached value of the PEI Services Table pointer.
  39
  40   Returns the cached value of the PEI Services Table pointer in a CPU specific manner
  41   as specified in the CPU binding section of the Platform Initialization Pre-EFI
  42   Initialization Core Interface Specification.
  43
  44   If the cached PEI Services Table pointer is NULL, then ASSERT().
  45
  46   @return  The pointer to PeiServices.
  47
  48 **/
  49 CONST EFI_PEI_SERVICES **
  50 EFIAPI
  51 GetPeiServicesTablePointer (
  52   VOID
  53   )
  54 {
  55   return (CONST EFI_PEI_SERVICES **)ArmReadTpidrurw();
  56 }
  57
  58 /**
  59 Perform CPU specific actions required to migrate the PEI Services Table
  60 pointer from temporary RAM to permanent RAM.
  61
  62 For IA32 CPUs, the PEI Services Table pointer is stored in the 4 bytes
  63 immediately preceding the Interrupt Descriptor Table (IDT) in memory.
  64 For X64 CPUs, the PEI Services Table pointer is stored in the 8 bytes
  65 immediately preceding the Interrupt Descriptor Table (IDT) in memory.
  66 For Itanium and ARM CPUs, a the PEI Services Table Pointer is stored in
  67 a dedicated CPU register.  This means that there is no memory storage
  68 associated with storing the PEI Services Table pointer, so no additional
  69 migration actions are required for Itanium or ARM CPUs.
  70
  71 **/
  72 VOID
  73 EFIAPI
  74 MigratePeiServicesTablePointer(
  75 VOID
  76 )
  77 {
  78   return;
  79 }