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/** @file
EDKII PEI Variable PPI provides an implementation of variables
intended for use as a means to store data in the PEI environment.
Copyright (c) 2022, Intel Corporation. All rights reserved.<BR>
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
#ifndef EDKII_PEI_VARIABLE_PPI_H_
#define EDKII_PEI_VARIABLE_PPI_H_
#define EDKII_PEI_VARIABLE_PPI_GUID \
{ \
0xe7b2cd04, 0x4b14, 0x44c2, { 0xb7, 0x48, 0xce, 0xaf, 0x2b, 0x66, 0x4a, 0xb0 } \
}
typedef struct _EDKII_PEI_VARIABLE_PPI EDKII_PEI_VARIABLE_PPI;
/**
This service retrieves a variable's value using its name and GUID.
Read the specified variable from the UEFI variable store. If the Data
buffer is too small to hold the contents of the variable,
the error EFI_BUFFER_TOO_SMALL is returned and DataSize is set to the
required buffer size to obtain the data.
@param[in] This A pointer to this instance of the EDKII_PEI_VARIABLE_PPI.
@param[in] VariableName A pointer to a null-terminated string that is the variable's name.
@param[in] VariableGuid A pointer to an EFI_GUID that is the variable's GUID. The combination of
VariableGuid and VariableName must be unique.
@param[out] Attributes If non-NULL, on return, points to the variable's attributes.
@param[in, out] DataSize On entry, points to the size in bytes of the Data buffer.
On return, points to the size of the data returned in Data.
@param[out] Data Points to the buffer which will hold the returned variable value.
May be NULL with a zero DataSize in order to determine the size of the
buffer needed.
@retval EFI_SUCCESS The variable was read successfully.
@retval EFI_NOT_FOUND The variable was not found.
@retval EFI_BUFFER_TOO_SMALL The DataSize is too small for the resulting data.
DataSize is updated with the size required for
the specified variable.
@retval EFI_INVALID_PARAMETER VariableName, VariableGuid, DataSize or Data is NULL.
@retval EFI_DEVICE_ERROR The variable could not be retrieved because of a device error.
**/
typedef
EFI_STATUS
(EFIAPI *EDKII_PEI_GET_VARIABLE)(
IN CONST EDKII_PEI_VARIABLE_PPI *This,
IN CONST CHAR16 *VariableName,
IN CONST EFI_GUID *VariableGuid,
OUT UINT32 *Attributes OPTIONAL,
IN OUT UINTN *DataSize,
OUT VOID *Data OPTIONAL
);
/**
Return the next variable name and GUID.
This function is called multiple times to retrieve the VariableName
and VariableGuid of all variables currently available in the system.
On each call, the previous results are passed into the interface,
and, on return, the interface returns the data for the next
variable. To get started, VariableName should initially contain L"\0"
and VariableNameSize should be sizeof(CHAR16). When the entire
variable list has been returned, EFI_NOT_FOUND is returned.
@param[in] This A pointer to this instance of the EDKII_PEI_VARIABLE_PPI.
@param[in, out] VariableNameSize On entry, points to the size of the buffer pointed to by VariableName.
On return, the size of the variable name buffer.
@param[in, out] VariableName On entry, a pointer to a null-terminated string that is the variable's name.
On return, points to the next variable's null-terminated name string.
@param[in, out] VariableGuid On entry, a pointer to an EFI_GUID that is the variable's GUID.
On return, a pointer to the next variable's GUID.
@retval EFI_SUCCESS The next variable name was read successfully.
@retval EFI_NOT_FOUND All variables have been enumerated.
@retval EFI_BUFFER_TOO_SMALL The VariableNameSize is too small for the resulting
data. VariableNameSize is updated with the size
required for the specified variable.
@retval EFI_INVALID_PARAMETER VariableName, VariableGuid or
VariableNameSize is NULL.
@retval EFI_DEVICE_ERROR The variable could not be retrieved because of a device error.
**/
typedef
EFI_STATUS
(EFIAPI *EDKII_PEI_GET_NEXT_VARIABLE_NAME)(
IN CONST EDKII_PEI_VARIABLE_PPI *This,
IN OUT UINTN *VariableNameSize,
IN OUT CHAR16 *VariableName,
IN OUT EFI_GUID *VariableGuid
);
/**
Sets the value of a variable.
@param[in] This A pointer to this instance of the EDKII_PEI_VARIABLE_PPI.
@param[in] VariableName A Null-terminated string that is the name of the vendor's variable.
Each VariableName is unique for each VendorGuid. VariableName must
contain 1 or more characters. If VariableName is an empty string,
then EFI_INVALID_PARAMETER is returned.
@param[in] VendorGuid A unique identifier for the vendor.
@param[in] Attributes Attributes bitmask to set for the variable.
@param[in] DataSize The size in bytes of the Data buffer. Unless the EFI_VARIABLE_APPEND_WRITE
attribute is set, a size of zero causes the variable to be deleted. When the
EFI_VARIABLE_APPEND_WRITE attribute is set, then a SetVariable() call with a
DataSize of zero will not cause any change to the variable value.
@param[in] Data The contents for the variable.
@retval EFI_SUCCESS The firmware has successfully stored the variable and its data as
defined by the Attributes.
@retval EFI_INVALID_PARAMETER An invalid combination of attribute bits, name, and GUID was supplied, or the
DataSize exceeds the maximum allowed.
@retval EFI_INVALID_PARAMETER VariableName is an empty string.
@retval EFI_OUT_OF_RESOURCES Not enough storage is available to hold the variable and its data.
@retval EFI_DEVICE_ERROR The variable could not be stored due to a hardware error.
@retval EFI_WRITE_PROTECTED The variable in question is read-only.
@retval EFI_WRITE_PROTECTED The variable in question cannot be deleted.
@retval EFI_SECURITY_VIOLATION The variable could not be written due to EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS,
or EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS, or
EFI_VARIABLE_ENHANCED_AUTHENTICATED_ACCESS being set. Writing to authenticated
variables is not supported in the PEI environment. Updates to authenticated
variables can be requested during PEI via the EFI_AUTHENTICATED_VARIABLE_HOB, but
these updates won't be written to non-volatile storage until later in DXE.
The EFI_AUTHENTICATED_VARIABLE_HOB is a HOB with the GUID
gEfiAuthenticatedVariableGuid. This HOB contains a VARIABLE_STORE_HEADER followed
by one or more UEFI variables, which are stored as DWORD aligned tuples of
(VARIABLE_HEADER + CHAR16 VariableName + VariableData).
See MdeModulePkg/Include/Guid/VariableFormat.h for these data structure
definitions and MdeModulePkg/Universal/Variable/RuntimeDxe/VariableParsing.c for
an example of how to parse these data structures.
@retval EFI_NOT_FOUND The variable trying to be updated or deleted was not found.
**/
typedef
EFI_STATUS
(EFIAPI *EDKII_PEI_SET_VARIABLE)(
IN CONST EDKII_PEI_VARIABLE_PPI *This,
IN CHAR16 *VariableName,
IN EFI_GUID *VendorGuid,
IN UINT32 Attributes,
IN UINTN DataSize,
IN VOID *Data
);
/**
Returns information about the UEFI variables.
@param[in] This A pointer to this instance of the EDKII_PEI_VARIABLE_PPI.
@param[in] Attributes Attributes bitmask to specify the type of variables on
which to return information.
@param[out] MaximumVariableStorageSize On output the maximum size of the storage space
available for the EFI variables associated with the
attributes specified.
@param[out] RemainingVariableStorageSize Returns the remaining size of the storage space
available for the EFI variables associated with the
attributes specified.
@param[out] MaximumVariableSize Returns the maximum size of the individual EFI
variables associated with the attributes specified.
@retval EFI_SUCCESS Valid answer returned.
@retval EFI_INVALID_PARAMETER An invalid combination of attribute bits was supplied
@retval EFI_UNSUPPORTED The attribute is not supported on this platform, and the
MaximumVariableStorageSize,
RemainingVariableStorageSize, MaximumVariableSize
are undefined.
**/
typedef
EFI_STATUS
(EFIAPI *EDKII_PEI_QUERY_VARIABLE_INFO)(
IN CONST EDKII_PEI_VARIABLE_PPI *This,
IN UINT32 Attributes,
OUT UINT64 *MaximumVariableStorageSize,
OUT UINT64 *RemainingVariableStorageSize,
OUT UINT64 *MaximumVariableSize
);
///
/// PEI Variable PPI is intended for use as a means
/// to store data in the PEI environment.
///
struct _EDKII_PEI_VARIABLE_PPI {
EDKII_PEI_GET_VARIABLE GetVariable;
EDKII_PEI_GET_NEXT_VARIABLE_NAME GetNextVariableName;
EDKII_PEI_SET_VARIABLE SetVariable;
EDKII_PEI_QUERY_VARIABLE_INFO QueryVariableInfo;
};
extern EFI_GUID gEdkiiPeiVariablePpiGuid;
#endif
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