audk/EmulatorPkg/Library/PeiServicesTablePointerLib/PeiServicesTablePointer.c

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/** @file
PEI Services Table Pointer Library.
This library is used for PEIM which does executed from flash device directly but
executed in memory.
Copyright (c) 2006 - 2010, Intel Corporation. All rights reserved.<BR>
Portiions copyrigth (c) 2011, Apple Inc. 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 <PiPei.h>
#include <Library/PeiServicesTablePointerLib.h>
#include <Library/DebugLib.h>
#include <Ppi/MemoryDiscovered.h>
CONST EFI_PEI_SERVICES **gPeiServices = NULL;
/**
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.
If PeiServicesTablePointer is NULL, then ASSERT().
@param PeiServicesTablePointer The address of PeiServices pointer.
**/
VOID
EFIAPI
SetPeiServicesTablePointer (
IN CONST EFI_PEI_SERVICES ** PeiServicesTablePointer
)
{
ASSERT (PeiServicesTablePointer != NULL);
ASSERT (*PeiServicesTablePointer != NULL);
gPeiServices = PeiServicesTablePointer;
}
/**
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
)
{
ASSERT (gPeiServices != NULL);
ASSERT (*gPeiServices != NULL);
return gPeiServices;
}
/**
Notification service to be called when gEmuThunkPpiGuid is installed.
@param PeiServices Indirect reference to the PEI Services Table.
@param NotifyDescriptor Address of the notification descriptor data structure. Type
EFI_PEI_NOTIFY_DESCRIPTOR is defined above.
@param Ppi Address of the PPI that was installed.
@retval EFI_STATUS This function will install a PPI to PPI database. The status
code will be the code for (*PeiServices)->InstallPpi.
**/
EFI_STATUS
EFIAPI
PeiServicesTablePointerNotifyCallback (
IN EFI_PEI_SERVICES **PeiServices,
IN EFI_PEI_NOTIFY_DESCRIPTOR *NotifyDescriptor,
IN VOID *Ppi
)
{
gPeiServices = (CONST EFI_PEI_SERVICES **)PeiServices;
return EFI_SUCCESS;
}
EFI_PEI_NOTIFY_DESCRIPTOR mNotifyOnThunkList = {
(EFI_PEI_PPI_DESCRIPTOR_NOTIFY_CALLBACK | EFI_PEI_PPI_DESCRIPTOR_TERMINATE_LIST),
&gEfiPeiMemoryDiscoveredPpiGuid,
PeiServicesTablePointerNotifyCallback
};
/**
Constructor register notification on when PPI updates. If PPI is
alreay installed registering the notify will cause the handle to
run.
@param FileHandle The handle of FFS header the loaded driver.
@param PeiServices The pointer to the PEI services.
@retval EFI_SUCCESS The constructor always returns EFI_SUCCESS.
**/
EFI_STATUS
EFIAPI
PeiServicesTablePointerLibConstructor (
IN EFI_PEI_FILE_HANDLE FileHandle,
IN CONST EFI_PEI_SERVICES **PeiServices
)
{
EFI_STATUS Status;
gPeiServices = (CONST EFI_PEI_SERVICES **)PeiServices;
// register to be told when PeiServices pointer is updated
Status = (*PeiServices)->NotifyPpi (PeiServices, &mNotifyOnThunkList);
ASSERT_EFI_ERROR (Status);
return Status;
}
/**
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.
**/
VOID
EFIAPI
MigratePeiServicesTablePointer (
VOID
)
{
//
// PEI Services Table pointer is cached in the global variable. No additional
// migration actions are required.
//
return;
}