MdePkg/Library/UefiPalLib/UefiPalLib.c

   1 /** @file
   2   PAL Library implementation built upon UEFI.
   3
   4   Copyright (c) 2007 - 2008, Intel Corporation All rights
   5   reserved. This program and the accompanying materials are
   6   licensed and made available under the terms and conditions of
   7   the BSD License which accompanies this distribution.  The full
   8   text of the license may be found at
   9   http://opensource.org/licenses/bsd-license.php
  10
  11   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  12   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  13
  14 **/
  15
  16 #include <PiDxe.h>
  17
  18 #include <IndustryStandard/Sal.h>
  19 #include <Library/UefiLib.h>
  20 #include <Library/BaseLib.h>
  21 #include <Library/DebugLib.h>
  22
  23 #include <Guid/SalSystemTable.h>
  24
  25 UINT64               mPalProcEntry;
  26
  27 /**
  28   Makes a PAL procedure call.
  29
  30   This is a wrapper function to make a PAL procedure call.  Based on the Index value,
  31   this API will make static or stacked PAL call. Architected procedures may be designated
  32   as required or optional.  If a PAL procedure is specified as optional, a unique return
  33   code of 0xFFFFFFFFFFFFFFFF is returned in the Status field of the PAL_CALL_RETURN structure.
  34   This indicates that the procedure is not present in this PAL implementation.  It is the
  35   caller's responsibility to check for this return code after calling any optional PAL
  36   procedure. No parameter checking is performed on the 4 input parameters, but there are
  37   some common rules that the caller should follow when making a PAL call.  Any address
  38   passed to PAL as buffers for return parameters must be 8-byte aligned.  Unaligned addresses
  39   may cause undefined results.  For those parameters defined as reserved or some fields
  40   defined as reserved must be zero filled or the invalid argument return value may be
  41   returned or undefined result may occur during the execution of the procedure.
  42   This function is only available on IPF.
  43
  44   @param Index - The PAL procedure Index number.
  45   @param Arg2  - The 2nd parameter for PAL procedure calls.
  46   @param Arg3  - The 3rd parameter for PAL procedure calls.
  47   @param Arg4  - The 4th parameter for PAL procedure calls.
  48
  49   @return structure returned from the PAL Call procedure, including the status and return value.
  50
  51 **/
  52 PAL_CALL_RETURN
  53 EFIAPI
  54 PalCall (
  55   IN UINT64                  Index,
  56   IN UINT64                  Arg2,
  57   IN UINT64                  Arg3,
  58   IN UINT64                  Arg4
  59   )
  60 {
  61   //
  62   // mPalProcEntry is initialized in library constructor as PAL entry.
  63   //
  64   return AsmPalCall (
  65            mPalProcEntry,
  66            Index,
  67            Arg2,
  68            Arg3,
  69            Arg4
  70            );
  71
  72 }
  73
  74 /**
  75   The constructor function of UEFI Pal Lib.
  76
  77   The constructor function looks up the SAL System Table in the EFI System Configuration
  78   Table. Once the SAL System Table is found, the PAL Entry Point in the SAL System Table
  79   will be derived and stored inot a global variable for library usage.
  80   It will ASSERT() if the SAL System Table cannot be found or the data in the SAL System
  81   Table is not the valid data.
  82
  83   @param  ImageHandle   The firmware allocated handle for the EFI image.
  84   @param  SystemTable   A pointer to the EFI System Table.
  85
  86   @retval EFI_SUCCESS   The constructor always returns EFI_SUCCESS.
  87
  88 **/
  89 EFI_STATUS
  90 EFIAPI
  91 UefiPalLibConstructor (
  92   IN EFI_HANDLE        ImageHandle,
  93   IN EFI_SYSTEM_TABLE  *SystemTable
  94   )
  95 {
  96   EFI_STATUS                     Status;
  97   SAL_ST_ENTRY_POINT_DESCRIPTOR  *SalStEntryDes;
  98   SAL_SYSTEM_TABLE_HEADER        *SalSystemTable;
  99
 100   Status = EfiGetSystemConfigurationTable (
 101              &gEfiSalSystemTableGuid,
 102              (VOID **) &SalSystemTable
 103              );
 104
 105   ASSERT_EFI_ERROR (Status);
 106
 107   //
 108   // Move the SAL System Table point to the first Entry
 109   // Due to the SAL Entry is in ascending order with the Entry type,
 110   // the type 0 Entry should be the first if exist.
 111   //
 112   SalStEntryDes = (SAL_ST_ENTRY_POINT_DESCRIPTOR *)(SalSystemTable + 1);
 113
 114   //
 115   // Assure the SAL ENTRY Type is 0
 116   //
 117   ASSERT (SalStEntryDes->Type == EFI_SAL_ST_ENTRY_POINT);
 118
 119   mPalProcEntry = SalStEntryDes->PalProcEntry;
 120   //
 121   // Make sure the PalCallAddress has the valid value
 122   //
 123   ASSERT (mPalProcEntry != 0);
 124
 125   return EFI_SUCCESS;
 126 }