Add check before use to make code run more safer.

[mirror_edk2.git] / MdePkg / Library / PeiServicesTablePointerLibIdt / PeiServicesTablePointer.c

diff --git a/MdePkg/Library/PeiServicesTablePointerLibIdt/PeiServicesTablePointer.c b/MdePkg/Library/PeiServicesTablePointerLibIdt/PeiServicesTablePointer.c
index aaae1828c2540034c8b11de264174fd49ecea381..c5fb8f552efe5e8e2d1a255346aee90257c31419 100644 (file)
--- a/MdePkg/Library/PeiServicesTablePointerLibIdt/PeiServicesTablePointer.c
+++ b/MdePkg/Library/PeiServicesTablePointerLibIdt/PeiServicesTablePointer.c
@@ -1,43 +1,77 @@
-/*++\r
-\r
-Copyright (c) 2006 Intel Corporation. All rights reserved\r
-This software and associated documentation (if any) is furnished\r
-under a license and may only be used or copied in accordance\r
-with the terms of the license. Except as permitted by such\r
-license, no part of this software or documentation may be\r
-reproduced, stored in a retrieval system, or transmitted in any\r
-form or by any means without the express written consent of\r
-Intel Corporation.\r
-\r
-  PEI Services Table Pointer Library.\r
+/** @file\r
+  PEI Services Table Pointer Library for IA-32 and x64.\r
+\r
+  According to PI specification, the peiservice pointer is stored prior at IDT\r
+  table in IA32 and x64 architecture.\r
   \r
---*/\r
+  Copyright (c) 2006 - 2008, Intel Corporation. All rights reserved.<BR>\r
+  This program and the accompanying materials                          \r
+  are licensed and made available under the terms and conditions of the BSD License         \r
+  which accompanies this distribution.  The full text of the license may be found at        \r
+  http://opensource.org/licenses/bsd-license.php.                                            \r
+\r
+  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,                     \r
+  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.             \r
+\r
+**/\r
+\r
+#include <PiPei.h>\r
 \r
-#include "InternalPeiServicesTablePointer.h"\r
+#include <Library/BaseLib.h>\r
+#include <Library/PeiServicesTablePointerLib.h>\r
+#include <Library/DebugLib.h>\r
 \r
 /**\r
+  Retrieves the cached value of the PEI Services Table pointer.\r
+\r
+  Returns the cached value of the PEI Services Table pointer in a CPU specific manner \r
+  as specified in the CPU binding section of the Platform Initialization Pre-EFI \r
+  Initialization Core Interface Specification.\r
   \r
-  The function returns the pointer to PeiServicee following\r
-  PI1.0.\r
-  \r
-  For IA32, the four-bytes field immediately prior to new IDT\r
-  base addres is used to save the EFI_PEI_SERVICES**.\r
-  For x64, the eight-bytes field immediately prior to new IDT\r
-  base addres is used to save the EFI_PEI_SERVICES**.\r
+  If the cached PEI Services Table pointer is NULL, then ASSERT().\r
 \r
-  @retval  The pointer to PeiServices.\r
+  @return  The pointer to PeiServices.\r
 \r
 **/\r
-EFI_PEI_SERVICES **\r
+CONST EFI_PEI_SERVICES **\r
 EFIAPI\r
 GetPeiServicesTablePointer (\r
   VOID\r
   )\r
 {\r
-  EFI_PEI_SERVICES  **PeiServices;\r
-\r
-  PeiServices = (EFI_PEI_SERVICES **) AsmPeiSevicesTablePointer ();\r
+  CONST EFI_PEI_SERVICES  **PeiServices;\r
+  IA32_DESCRIPTOR   Idtr;\r
+  \r
+  AsmReadIdtr (&Idtr);\r
+  PeiServices = (CONST EFI_PEI_SERVICES **) (*(UINTN*)(Idtr.Base - sizeof (UINTN)));\r
   ASSERT (PeiServices != NULL);\r
   return PeiServices;\r
 }\r
 \r
+/**\r
+  Caches a pointer PEI Services Table. \r
+ \r
+  Caches the pointer to the PEI Services Table specified by PeiServicesTablePointer \r
+  in a CPU specific manner as specified in the CPU binding section of the Platform Initialization \r
+  Pre-EFI Initialization Core Interface Specification. \r
+  The function set the pointer of PEI services immediately preceding the IDT table\r
+  according to PI specification.\r
+  \r
+  If PeiServicesTablePointer is NULL, then ASSERT().\r
+  \r
+  @param    PeiServicesTablePointer   The address of PeiServices pointer.\r
+**/\r
+VOID\r
+EFIAPI\r
+SetPeiServicesTablePointer (\r
+  IN CONST EFI_PEI_SERVICES ** PeiServicesTablePointer\r
+  )\r
+{\r
+  IA32_DESCRIPTOR   Idtr;\r
+  \r
+  ASSERT (PeiServicesTablePointer != NULL);\r
+  AsmReadIdtr (&Idtr);\r
+  (*(UINTN*)(Idtr.Base - sizeof (UINTN))) = (UINTN)PeiServicesTablePointer;\r
+}\r
+\r
+\r