EmulatorPkg/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   Portiions copyrigth (c) 2011, Apple Inc. All rights reserved.
   9   SPDX-License-Identifier: BSD-2-Clause-Patent
  10
  11 **/
  12
  13 #include <PiPei.h>
  14 #include <Library/PeiServicesTablePointerLib.h>
  15 #include <Library/DebugLib.h>
  16
  17 #include <Ppi/MemoryDiscovered.h>
  18
  19 CONST EFI_PEI_SERVICES  **gPeiServices = NULL;
  20
  21 /**
  22   Caches a pointer PEI Services Table.
  23
  24   Caches the pointer to the PEI Services Table specified by PeiServicesTablePointer
  25   in a CPU specific manner as specified in the CPU binding section of the Platform Initialization
  26   Pre-EFI Initialization Core Interface Specification.
  27
  28   If PeiServicesTablePointer is NULL, then ASSERT().
  29
  30   @param    PeiServicesTablePointer   The address of PeiServices pointer.
  31 **/
  32 VOID
  33 EFIAPI
  34 SetPeiServicesTablePointer (
  35   IN CONST EFI_PEI_SERVICES  **PeiServicesTablePointer
  36   )
  37 {
  38   ASSERT (PeiServicesTablePointer != NULL);
  39   ASSERT (*PeiServicesTablePointer != NULL);
  40   gPeiServices = 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   ASSERT (gPeiServices != NULL);
  62   ASSERT (*gPeiServices != NULL);
  63   return gPeiServices;
  64 }
  65
  66 /**
  67   Notification service to be called when gEmuThunkPpiGuid is installed.
  68
  69   @param  PeiServices                 Indirect reference to the PEI Services Table.
  70   @param  NotifyDescriptor          Address of the notification descriptor data structure. Type
  71           EFI_PEI_NOTIFY_DESCRIPTOR is defined above.
  72   @param  Ppi                             Address of the PPI that was installed.
  73
  74   @retval   EFI_STATUS                This function will install a PPI to PPI database. The status
  75                                                   code will be the code for (*PeiServices)->InstallPpi.
  76
  77 **/
  78 EFI_STATUS
  79 EFIAPI
  80 PeiServicesTablePointerNotifyCallback (
  81   IN EFI_PEI_SERVICES           **PeiServices,
  82   IN EFI_PEI_NOTIFY_DESCRIPTOR  *NotifyDescriptor,
  83   IN VOID                       *Ppi
  84   )
  85 {
  86   gPeiServices = (CONST EFI_PEI_SERVICES  **)PeiServices;
  87
  88   return EFI_SUCCESS;
  89 }
  90
  91 EFI_PEI_NOTIFY_DESCRIPTOR  mNotifyOnThunkList = {
  92   (EFI_PEI_PPI_DESCRIPTOR_NOTIFY_CALLBACK | EFI_PEI_PPI_DESCRIPTOR_TERMINATE_LIST),
  93   &gEfiPeiMemoryDiscoveredPpiGuid,
  94   PeiServicesTablePointerNotifyCallback
  95 };
  96
  97 /**
  98   Constructor register notification on when PPI updates. If PPI is
  99   alreay installed registering the notify will cause the handle to
 100   run.
 101
 102   @param  FileHandle   The handle of FFS header the loaded driver.
 103   @param  PeiServices  The pointer to the PEI services.
 104
 105   @retval EFI_SUCCESS  The constructor always returns EFI_SUCCESS.
 106
 107 **/
 108 EFI_STATUS
 109 EFIAPI
 110 PeiServicesTablePointerLibConstructor (
 111   IN EFI_PEI_FILE_HANDLE     FileHandle,
 112   IN CONST EFI_PEI_SERVICES  **PeiServices
 113   )
 114 {
 115   EFI_STATUS  Status;
 116
 117   gPeiServices = (CONST EFI_PEI_SERVICES  **)PeiServices;
 118
 119   // register to be told when PeiServices pointer is updated
 120   Status = (*PeiServices)->NotifyPpi (PeiServices, &mNotifyOnThunkList);
 121   ASSERT_EFI_ERROR (Status);
 122   return Status;
 123 }
 124
 125 /**
 126   Perform CPU specific actions required to migrate the PEI Services Table
 127   pointer from temporary RAM to permanent RAM.
 128
 129   For IA32 CPUs, the PEI Services Table pointer is stored in the 4 bytes
 130   immediately preceding the Interrupt Descriptor Table (IDT) in memory.
 131   For X64 CPUs, the PEI Services Table pointer is stored in the 8 bytes
 132   immediately preceding the Interrupt Descriptor Table (IDT) in memory.
 133   For Itanium and ARM CPUs, a the PEI Services Table Pointer is stored in
 134   a dedicated CPU register.  This means that there is no memory storage
 135   associated with storing the PEI Services Table pointer, so no additional
 136   migration actions are required for Itanium or ARM CPUs.
 137
 138 **/
 139 VOID
 140 EFIAPI
 141 MigratePeiServicesTablePointer (
 142   VOID
 143   )
 144 {
 145   //
 146   //  PEI Services Table pointer is cached in the global variable. No additional
 147   //  migration actions are required.
 148   //
 149   return;
 150 }