MdePkg/Library/PeiServicesTablePointerLibIdt/PeiServicesTablePointer.c

   1 /** @file
   2   PEI Services Table Pointer Library for IA-32 and x64.
   3
   4   According to PI specification, the peiservice pointer is stored prior at IDT
   5   table in IA32 and x64 architecture.
   6
   7   Copyright (c) 2006 - 2014, Intel Corporation. All rights reserved.<BR>
   8   This program and the accompanying materials
   9   are licensed and made available under the terms and conditions of the BSD License
  10   which accompanies this distribution.  The full text of the license may be found at
  11   http://opensource.org/licenses/bsd-license.php.
  12
  13   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  14   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  15
  16 **/
  17
  18 #include <PiPei.h>
  19
  20 #include <Library/BaseLib.h>
  21 #include <Library/PeiServicesTablePointerLib.h>
  22 #include <Library/DebugLib.h>
  23 #include <Library/BaseMemoryLib.h>
  24
  25 /**
  26   Retrieves the cached value of the PEI Services Table pointer.
  27
  28   Returns the cached value of the PEI Services Table pointer in a CPU specific manner
  29   as specified in the CPU binding section of the Platform Initialization Pre-EFI
  30   Initialization Core Interface Specification.
  31
  32   If the cached PEI Services Table pointer is NULL, then ASSERT().
  33
  34   @return  The pointer to PeiServices.
  35
  36 **/
  37 CONST EFI_PEI_SERVICES **
  38 EFIAPI
  39 GetPeiServicesTablePointer (
  40   VOID
  41   )
  42 {
  43   CONST EFI_PEI_SERVICES  **PeiServices;
  44   IA32_DESCRIPTOR   Idtr;
  45
  46   AsmReadIdtr (&Idtr);
  47   PeiServices = (CONST EFI_PEI_SERVICES **) (*(UINTN*)(Idtr.Base - sizeof (UINTN)));
  48   ASSERT (PeiServices != NULL);
  49   return PeiServices;
  50 }
  51
  52 /**
  53   Caches a pointer PEI Services Table.
  54
  55   Caches the pointer to the PEI Services Table specified by PeiServicesTablePointer
  56   in a CPU specific manner as specified in the CPU binding section of the Platform Initialization
  57   Pre-EFI Initialization Core Interface Specification.
  58   The function set the pointer of PEI services immediately preceding the IDT table
  59   according to PI specification.
  60
  61   If PeiServicesTablePointer is NULL, then ASSERT().
  62
  63   @param    PeiServicesTablePointer   The address of PeiServices pointer.
  64 **/
  65 VOID
  66 EFIAPI
  67 SetPeiServicesTablePointer (
  68   IN CONST EFI_PEI_SERVICES ** PeiServicesTablePointer
  69   )
  70 {
  71   IA32_DESCRIPTOR        Idtr;
  72
  73   ASSERT (PeiServicesTablePointer != NULL);
  74   AsmReadIdtr (&Idtr);
  75   (*(UINTN*)(Idtr.Base - sizeof (UINTN))) = (UINTN)PeiServicesTablePointer;
  76 }
  77
  78 /**
  79   Perform CPU specific actions required to migrate the PEI Services Table
  80   pointer from temporary RAM to permanent RAM.
  81
  82   For IA32 CPUs, the PEI Services Table pointer is stored in the 4 bytes
  83   immediately preceding the Interrupt Descriptor Table (IDT) in memory.
  84   For X64 CPUs, the PEI Services Table pointer is stored in the 8 bytes
  85   immediately preceding the Interrupt Descriptor Table (IDT) in memory.
  86   For Itanium and ARM CPUs, a the PEI Services Table Pointer is stored in
  87   a dedicated CPU register.  This means that there is no memory storage
  88   associated with storing the PEI Services Table pointer, so no additional
  89   migration actions are required for Itanium or ARM CPUs.
  90
  91   If The cached PEI Services Table pointer is NULL, then ASSERT().
  92   If the permanent memory is allocated failed, then ASSERT().
  93 **/
  94 VOID
  95 EFIAPI
  96 MigratePeiServicesTablePointer (
  97   )
  98 {
  99   EFI_STATUS             Status;
 100   IA32_DESCRIPTOR        Idtr;
 101   EFI_PHYSICAL_ADDRESS   IdtBase;
 102   CONST EFI_PEI_SERVICES  **PeiServices;
 103
 104   //
 105   // Get PEI Services Table pointer
 106   //
 107   AsmReadIdtr (&Idtr);
 108   PeiServices = (CONST EFI_PEI_SERVICES **) (*(UINTN*)(Idtr.Base - sizeof (UINTN)));
 109   ASSERT (PeiServices != NULL);
 110   //
 111   // Allocate the permanent memory.
 112   //
 113   Status = (*PeiServices)->AllocatePages (
 114                             PeiServices,
 115                             EfiBootServicesCode,
 116                             EFI_SIZE_TO_PAGES(Idtr.Limit + 1 + sizeof (UINTN)),
 117                             &IdtBase
 118                             );
 119   ASSERT_EFI_ERROR (Status);
 120   //
 121   // Idt table needs to be migrated into memory.
 122   //
 123   CopyMem ((VOID *) (UINTN) IdtBase, (VOID *) (Idtr.Base - sizeof (UINTN)), Idtr.Limit + 1 + sizeof (UINTN));
 124   Idtr.Base = (UINTN) IdtBase + sizeof (UINTN);
 125   AsmWriteIdtr (&Idtr);
 126
 127   return;
 128 }
 129
 130