audk/MdePkg/Library/PeiServicesTablePointerLibIdt/PeiServicesTablePointer.c

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/** @file
PEI Services Table Pointer Library for IA-32 and X64.
Copyright (c) 2006 - 2007, Intel Corporation.<BR>
All rights reserved. This program and the accompanying materials
are licensed and made available under the terms and conditions of the BSD License
which accompanies this distribution. The full text of the license may be found at
http://opensource.org/licenses/bsd-license.php
THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
**/
#include "InternalPeiServicesTablePointer.h"
/**
The function returns the pointer to PeiServicee following
PI1.0.
For IA32, the four-bytes field immediately prior to new IDT
base addres is used to save the EFI_PEI_SERVICES**.
For x64, the eight-bytes field immediately prior to new IDT
base addres is used to save the EFI_PEI_SERVICES**
@retval The pointer to PeiServices.
**/
EFI_PEI_SERVICES **
EFIAPI
GetPeiServicesTablePointer (
VOID
)
{
EFI_PEI_SERVICES **PeiServices;
IA32_DESCRIPTOR Idtr;
AsmReadIdtr (&Idtr);
PeiServices = (EFI_PEI_SERVICES **) (*(UINTN*)(Idtr.Base - 4));
ASSERT (PeiServices != NULL);
return PeiServices;
}
/**
The function returns the pointer to PeiServicee following
PI1.0.
For IA32, the four-bytes field immediately prior to new IDT
base addres is used to save the EFI_PEI_SERVICES**.
For x64, the eight-bytes field immediately prior to new IDT
base addres is used to save the EFI_PEI_SERVICES**
@retval The pointer to PeiServices.
**/
VOID
EFIAPI
SetPeiServicesTablePointer (
EFI_PEI_SERVICES ** PeiServicesTablePointer
)
{
IA32_DESCRIPTOR Idtr;
AsmReadIdtr (&Idtr);
(*(UINTN*)(Idtr.Base - 4)) = (UINTN)PeiServicesTablePointer;
}
/**
After memory initialization in PEI phase, the IDT table in temporary memory should
be migrated to memory, and the address of PeiServicesPointer also need to be updated
immediately preceding the new IDT table.
@param PeiServices The address of PeiServices pointer.
**/
VOID
EFIAPI
MigrateIdtTable (
IN EFI_PEI_SERVICES **PeiServices
)
{
UINTN Size;
VOID *NewBase;
EFI_STATUS Status;
IA32_DESCRIPTOR Idtr;
AsmReadIdtr (&Idtr);
Size = sizeof(UINTN) + (Idtr.Limit + 1);
Status = PeiServicesAllocatePool (Size, &NewBase);
ASSERT_EFI_ERROR (Status);
CopyMem ((VOID*)((UINTN)NewBase + sizeof(UINTN)), (VOID*)Idtr.Base, (Idtr.Limit + 1));
Idtr.Base = (UINTN)NewBase + sizeof(UINTN);
AsmWriteIdtr (&Idtr);
SetPeiServicesTablePointer(PeiServices);
}