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   This program and the accompanying materials
  10   are licensed and made available under the terms and conditions of the BSD License
  11   which accompanies this distribution.  The full text of the license may be found at
  12   http://opensource.org/licenses/bsd-license.php.
  13
  14   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  15   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  16
  17 **/
  18
  19 #include <PiPei.h>
  20 #include <Library/PeiServicesTablePointerLib.h>
  21 #include <Library/ArmLib.h>
  22 #include <Library/DebugLib.h>
  23
  24 /**
  25   Caches a pointer PEI Services Table.
  26
  27   Caches the pointer to the PEI Services Table specified by PeiServicesTablePointer
  28   in a platform specific manner.
  29
  30   If PeiServicesTablePointer is NULL, then ASSERT().
  31
  32   @param    PeiServicesTablePointer   The address of PeiServices pointer.
  33 **/
  34 VOID
  35 EFIAPI
  36 SetPeiServicesTablePointer (
  37   IN CONST EFI_PEI_SERVICES ** PeiServicesTablePointer
  38   )
  39 {
  40   ArmWriteTpidrurw((UINTN)PeiServicesTablePointer);
  41 }
  42
  43 /**
  44   Retrieves the cached value of the PEI Services Table pointer.
  45
  46   Returns the cached value of the PEI Services Table pointer in a CPU specific manner
  47   as specified in the CPU binding section of the Platform Initialization Pre-EFI
  48   Initialization Core Interface Specification.
  49
  50   If the cached PEI Services Table pointer is NULL, then ASSERT().
  51
  52   @return  The pointer to PeiServices.
  53
  54 **/
  55 CONST EFI_PEI_SERVICES **
  56 EFIAPI
  57 GetPeiServicesTablePointer (
  58   VOID
  59   )
  60 {
  61   return (CONST EFI_PEI_SERVICES **)ArmReadTpidrurw();
  62 }
  63
  64 /**
  65 Perform CPU specific actions required to migrate the PEI Services Table
  66 pointer from temporary RAM to permanent RAM.
  67
  68 For IA32 CPUs, the PEI Services Table pointer is stored in the 4 bytes
  69 immediately preceding the Interrupt Descriptor Table (IDT) in memory.
  70 For X64 CPUs, the PEI Services Table pointer is stored in the 8 bytes
  71 immediately preceding the Interrupt Descriptor Table (IDT) in memory.
  72 For Itanium and ARM CPUs, a the PEI Services Table Pointer is stored in
  73 a dedicated CPU register.  This means that there is no memory storage
  74 associated with storing the PEI Services Table pointer, so no additional
  75 migration actions are required for Itanium or ARM CPUs.
  76
  77 **/
  78 VOID
  79 EFIAPI
  80 MigratePeiServicesTablePointer(
  81 VOID
  82 )
  83 {
  84   return;
  85 }