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/** @file
PEI Services Table Pointer Library for IA-32 and x64.
According to PI specification, the peiservice pointer is stored prior at IDT
table in IA32 and x64 architecture.
Copyright (c) 2006 - 2014, Intel Corporation. All rights reserved.<BR>
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 <PiPei.h>
#include <Library/BaseLib.h>
#include <Library/PeiServicesTablePointerLib.h>
#include <Library/DebugLib.h>
#include <Library/BaseMemoryLib.h>
/**
Retrieves the cached value of the PEI Services Table pointer.
Returns the cached value of the PEI Services Table pointer in a CPU specific manner
as specified in the CPU binding section of the Platform Initialization Pre-EFI
Initialization Core Interface Specification.
If the cached PEI Services Table pointer is NULL, then ASSERT().
@return The pointer to PeiServices.
**/
CONST EFI_PEI_SERVICES **
EFIAPI
GetPeiServicesTablePointer (
VOID
)
{
CONST EFI_PEI_SERVICES **PeiServices;
IA32_DESCRIPTOR Idtr;
AsmReadIdtr (&Idtr);
PeiServices = (CONST EFI_PEI_SERVICES **) (*(UINTN*)(Idtr.Base - sizeof (UINTN)));
ASSERT (PeiServices != NULL);
return PeiServices;
}
/**
Caches a pointer PEI Services Table.
Caches the pointer to the PEI Services Table specified by PeiServicesTablePointer
in a CPU specific manner as specified in the CPU binding section of the Platform Initialization
Pre-EFI Initialization Core Interface Specification.
The function set the pointer of PEI services immediately preceding the IDT table
according to PI specification.
If PeiServicesTablePointer is NULL, then ASSERT().
@param PeiServicesTablePointer The address of PeiServices pointer.
**/
VOID
EFIAPI
SetPeiServicesTablePointer (
IN CONST EFI_PEI_SERVICES ** PeiServicesTablePointer
)
{
IA32_DESCRIPTOR Idtr;
ASSERT (PeiServicesTablePointer != NULL);
AsmReadIdtr (&Idtr);
(*(UINTN*)(Idtr.Base - sizeof (UINTN))) = (UINTN)PeiServicesTablePointer;
}
/**
Perform CPU specific actions required to migrate the PEI Services Table
pointer from temporary RAM to permanent RAM.
For IA32 CPUs, the PEI Services Table pointer is stored in the 4 bytes
immediately preceding the Interrupt Descriptor Table (IDT) in memory.
For X64 CPUs, the PEI Services Table pointer is stored in the 8 bytes
immediately preceding the Interrupt Descriptor Table (IDT) in memory.
For Itanium and ARM CPUs, a the PEI Services Table Pointer is stored in
a dedicated CPU register. This means that there is no memory storage
associated with storing the PEI Services Table pointer, so no additional
migration actions are required for Itanium or ARM CPUs.
If The cached PEI Services Table pointer is NULL, then ASSERT().
If the permanent memory is allocated failed, then ASSERT().
**/
VOID
EFIAPI
MigratePeiServicesTablePointer (
VOID
)
{
EFI_STATUS Status;
IA32_DESCRIPTOR Idtr;
EFI_PHYSICAL_ADDRESS IdtBase;
CONST EFI_PEI_SERVICES **PeiServices;
//
// Get PEI Services Table pointer
//
AsmReadIdtr (&Idtr);
PeiServices = (CONST EFI_PEI_SERVICES **) (*(UINTN*)(Idtr.Base - sizeof (UINTN)));
ASSERT (PeiServices != NULL);
//
// Allocate the permanent memory.
//
Status = (*PeiServices)->AllocatePages (
PeiServices,
EfiBootServicesCode,
EFI_SIZE_TO_PAGES(Idtr.Limit + 1 + sizeof (UINTN)),
&IdtBase
);
ASSERT_EFI_ERROR (Status);
//
// Idt table needs to be migrated into memory.
//
CopyMem ((VOID *) (UINTN) IdtBase, (VOID *) (Idtr.Base - sizeof (UINTN)), Idtr.Limit + 1 + sizeof (UINTN));
Idtr.Base = (UINTN) IdtBase + sizeof (UINTN);
AsmWriteIdtr (&Idtr);
return;
}
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