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 - 2018, Intel Corporation. All rights reserved.<BR>
   8   SPDX-License-Identifier: BSD-2-Clause-Patent
   9
  10 **/
  11
  12 #include <PiPei.h>
  13
  14 #include <Library/BaseLib.h>
  15 #include <Library/PeiServicesTablePointerLib.h>
  16 #include <Library/DebugLib.h>
  17 #include <Library/BaseMemoryLib.h>
  18
  19 /**
  20   Retrieves the cached value of the PEI Services Table pointer.
  21
  22   Returns the cached value of the PEI Services Table pointer in a CPU specific manner
  23   as specified in the CPU binding section of the Platform Initialization Pre-EFI
  24   Initialization Core Interface Specification.
  25
  26   If the cached PEI Services Table pointer is NULL, then ASSERT().
  27
  28   @return  The pointer to PeiServices.
  29
  30 **/
  31 CONST EFI_PEI_SERVICES **
  32 EFIAPI
  33 GetPeiServicesTablePointer (
  34   VOID
  35   )
  36 {
  37   CONST EFI_PEI_SERVICES  **PeiServices;
  38   IA32_DESCRIPTOR         Idtr;
  39
  40   AsmReadIdtr (&Idtr);
  41   PeiServices = (CONST EFI_PEI_SERVICES **)(*(UINTN *)(Idtr.Base - sizeof (UINTN)));
  42   ASSERT (PeiServices != NULL);
  43   return PeiServices;
  44 }
  45
  46 /**
  47   Caches a pointer PEI Services Table.
  48
  49   Caches the pointer to the PEI Services Table specified by PeiServicesTablePointer
  50   in a CPU specific manner as specified in the CPU binding section of the Platform Initialization
  51   Pre-EFI Initialization Core Interface Specification.
  52   The function set the pointer of PEI services immediately preceding the IDT table
  53   according to PI specification.
  54
  55   If PeiServicesTablePointer is NULL, then ASSERT().
  56
  57   @param    PeiServicesTablePointer   The address of PeiServices pointer.
  58 **/
  59 VOID
  60 EFIAPI
  61 SetPeiServicesTablePointer (
  62   IN CONST EFI_PEI_SERVICES  **PeiServicesTablePointer
  63   )
  64 {
  65   IA32_DESCRIPTOR  Idtr;
  66
  67   ASSERT (PeiServicesTablePointer != NULL);
  68   AsmReadIdtr (&Idtr);
  69   (*(UINTN *)(Idtr.Base - sizeof (UINTN))) = (UINTN)PeiServicesTablePointer;
  70 }
  71
  72 /**
  73   Perform CPU specific actions required to migrate the PEI Services Table
  74   pointer from temporary RAM to permanent RAM.
  75
  76   For IA32 CPUs, the PEI Services Table pointer is stored in the 4 bytes
  77   immediately preceding the Interrupt Descriptor Table (IDT) in memory.
  78   For X64 CPUs, the PEI Services Table pointer is stored in the 8 bytes
  79   immediately preceding the Interrupt Descriptor Table (IDT) in memory.
  80   For Itanium and ARM CPUs, a the PEI Services Table Pointer is stored in
  81   a dedicated CPU register.  This means that there is no memory storage
  82   associated with storing the PEI Services Table pointer, so no additional
  83   migration actions are required for Itanium or ARM CPUs.
  84
  85   If The cached PEI Services Table pointer is NULL, then ASSERT().
  86   If the permanent memory is allocated failed, then ASSERT().
  87 **/
  88 VOID
  89 EFIAPI
  90 MigratePeiServicesTablePointer (
  91   VOID
  92   )
  93 {
  94   EFI_STATUS              Status;
  95   IA32_DESCRIPTOR         Idtr;
  96   EFI_PHYSICAL_ADDRESS    IdtBase;
  97   CONST EFI_PEI_SERVICES  **PeiServices;
  98
  99   //
 100   // Get PEI Services Table pointer
 101   //
 102   AsmReadIdtr (&Idtr);
 103   PeiServices = (CONST EFI_PEI_SERVICES **)(*(UINTN *)(Idtr.Base - sizeof (UINTN)));
 104   ASSERT (PeiServices != NULL);
 105   //
 106   // Allocate the permanent memory.
 107   //
 108   Status = (*PeiServices)->AllocatePages (
 109                              PeiServices,
 110                              EfiBootServicesCode,
 111                              EFI_SIZE_TO_PAGES (Idtr.Limit + 1 + sizeof (UINTN)),
 112                              &IdtBase
 113                              );
 114   ASSERT_EFI_ERROR (Status);
 115   //
 116   // Idt table needs to be migrated into memory.
 117   //
 118   CopyMem ((VOID *)(UINTN)IdtBase, (VOID *)(Idtr.Base - sizeof (UINTN)), Idtr.Limit + 1 + sizeof (UINTN));
 119   Idtr.Base = (UINTN)IdtBase + sizeof (UINTN);
 120   AsmWriteIdtr (&Idtr);
 121
 122   return;
 123 }