MdePkg/Include/Library/UefiRuntimeLib.h

   1 /** @file
   2   Provides library functions for each of the UEFI Runtime Services.
   3   Only available to DXE and UEFI module types.
   4
   5 Copyright (c) 2006 - 2008, Intel Corporation<BR>
   6 All rights reserved. This program and the accompanying materials
   7 are licensed and made available under the terms and conditions of the BSD License
   8 which accompanies this distribution.  The full text of the license may be found at
   9 http://opensource.org/licenses/bsd-license.php
  10
  11 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  12 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  13 **/
  14
  15 #ifndef __UEFI_RUNTIME_LIB__
  16 #define __UEFI_RUNTIME_LIB__
  17
  18
  19 extern const EFI_EVENT_NOTIFY _gDriverExitBootServicesEvent[];
  20
  21 extern const EFI_EVENT_NOTIFY _gDriverSetVirtualAddressMapEvent[];
  22
  23 /**
  24   This function allows the caller to determine if UEFI ExitBootServices() has been called.
  25
  26   This function returns TRUE after all the EVT_SIGNAL_EXIT_BOOT_SERVICES functions have
  27   executed as a result of the OS calling ExitBootServices().  Prior to this time FALSE
  28   is returned. This function is used by runtime code to decide it is legal to access
  29   services that go away after ExitBootServices().
  30
  31   @retval  TRUE  The system has finished executing the EVT_SIGNAL_EXIT_BOOT_SERVICES event.
  32   @retval  FALSE The system has not finished executing the EVT_SIGNAL_EXIT_BOOT_SERVICES event.
  33
  34 **/
  35 BOOLEAN
  36 EFIAPI
  37 EfiAtRuntime (
  38   VOID
  39   );
  40
  41 /**
  42   This function allows the caller to determine if UEFI SetVirtualAddressMap() has been called.
  43
  44   This function returns TRUE after all the EVT_SIGNAL_VIRTUAL_ADDRESS_CHANGE functions have
  45   executed as a result of the OS calling SetVirtualAddressMap(). Prior to this time FALSE
  46   is returned. This function is used by runtime code to decide it is legal to access services
  47   that go away after SetVirtualAddressMap().
  48
  49   @retval  TRUE  The system has finished executing the EVT_SIGNAL_VIRTUAL_ADDRESS_CHANGE event.
  50   @retval  FALSE The system has not finished executing the EVT_SIGNAL_VIRTUAL_ADDRESS_CHANGE event.
  51
  52 **/
  53 BOOLEAN
  54 EFIAPI
  55 EfiGoneVirtual (
  56   VOID
  57   );
  58
  59 /**
  60   This service is a wrapper for the UEFI Runtime Service GetTime().
  61
  62   The GetTime() function returns a time that was valid sometime during the call to the function.
  63   While the returned EFI_TIME structure contains TimeZone and Daylight savings time information,
  64   the actual clock does not maintain these values. The current time zone and daylight saving time
  65   information returned by GetTime() are the values that were last set via SetTime().
  66   The GetTime() function should take approximately the same amount of time to read the time each
  67   time it is called. All reported device capabilities are to be rounded up.
  68   During runtime, if a PC-AT CMOS device is present in the platform the caller must synchronize
  69   access to the device before calling GetTime().
  70
  71   @param  Time         A pointer to storage to receive a snapshot of the current time.
  72   @param  Capabilities An optional pointer to a buffer to receive the real time clock device's
  73                        capabilities.
  74
  75   @retval  EFI_SUCCESS            The operation completed successfully.
  76   @retval  EFI_INVALID_PARAMETER  Time is NULL.
  77   @retval  EFI_DEVICE_ERROR       The time could not be retrieved due to a hardware error.
  78
  79 **/
  80 EFI_STATUS
  81 EFIAPI
  82 EfiGetTime (
  83   OUT EFI_TIME                    *Time,
  84   OUT EFI_TIME_CAPABILITIES       *Capabilities  OPTIONAL
  85   );
  86
  87 /**
  88   This service is a wrapper for the UEFI Runtime Service SetTime().
  89
  90   The SetTime() function sets the real time clock device to the supplied time, and records the
  91   current time zone and daylight savings time information. The SetTime() function is not allowed
  92   to loop based on the current time. For example, if the device does not support a hardware reset
  93   for the sub-resolution time, the code is not to implement the feature by waiting for the time to
  94   wrap.
  95   During runtime, if a PC-AT CMOS device is present in the platform the caller must synchronize
  96   access to the device before calling SetTime().
  97
  98   @param  Time  A pointer to the current time. Type EFI_TIME is defined in the GetTime()
  99                 function description. Full error checking is performed on the different
 100                 fields of the EFI_TIME structure (refer to the EFI_TIME definition in the
 101                 GetTime() function description for full details), and EFI_INVALID_PARAMETER
 102                 is returned if any field is out of range.
 103
 104   @retval  EFI_SUCCESS            The operation completed successfully.
 105   @retval  EFI_INVALID_PARAMETER  A time field is out of range.
 106   @retval  EFI_DEVICE_ERROR       The time could not be set due to a hardware error.
 107
 108 **/
 109 EFI_STATUS
 110 EFIAPI
 111 EfiSetTime (
 112   IN EFI_TIME                   *Time
 113   );
 114
 115 /**
 116   Returns the current wakeup alarm clock setting.
 117
 118   The alarm clock time may be rounded from the set alarm clock time to be within the resolution
 119   of the alarm clock device. The resolution of the alarm clock device is defined to be one second.
 120   During runtime, if a PC-AT CMOS device is present in the platform the caller must synchronize
 121   access to the device before calling GetWakeupTime().
 122
 123   @param  Enabled  Indicates if the alarm is currently enabled or disabled.
 124   @param  Pending  Indicates if the alarm signal is pending and requires acknowledgement.
 125   @param  Time     The current alarm setting. Type EFI_TIME is defined in the GetTime()
 126                    function description.
 127
 128   @retval  EFI_SUCCESS           The alarm settings were returned.
 129   @retval  EFI_INVALID_PARAMETER  Enabled is NULL.
 130   @retval  EFI_INVALID_PARAMETER  Pending is NULL.
 131   @retval  EFI_INVALID_PARAMETER  Time is NULL.
 132   @retval  EFI_DEVICE_ERROR       The wakeup time could not be retrieved due to a hardware error.
 133   @retval  EFI_UNSUPPORTED        A wakeup timer is not supported on this platform.
 134
 135 **/
 136 EFI_STATUS
 137 EFIAPI
 138 EfiGetWakeupTime (
 139   OUT BOOLEAN                     *Enabled,
 140   OUT BOOLEAN                     *Pending,
 141   OUT EFI_TIME                    *Time
 142   );
 143
 144 /**
 145   Sets the system wakeup alarm clock time.
 146
 147   @param  Enable  Enable or disable the wakeup alarm.
 148   @param  Time    If Enable is TRUE, the time to set the wakeup alarm for. Type EFI_TIME
 149                   is defined in the GetTime() function description. If Enable is FALSE,
 150                   then this parameter is optional, and may be NULL.
 151
 152   @retval  EFI_SUCCESS            If Enable is TRUE, then the wakeup alarm was enabled.
 153                                   If Enable is FALSE, then the wakeup alarm was disabled.
 154   @retval  EFI_INVALID_PARAMETER  A time field is out of range.
 155   @retval  EFI_DEVICE_ERROR       The wakeup time could not be set due to a hardware error.
 156   @retval  EFI_UNSUPPORTED        A wakeup timer is not supported on this platform.
 157
 158 **/
 159 EFI_STATUS
 160 EFIAPI
 161 EfiSetWakeupTime (
 162   IN BOOLEAN                      Enable,
 163   IN EFI_TIME                     *Time   OPTIONAL
 164   );
 165
 166 /**
 167   Return value of variable.
 168
 169   @param  VariableName the name of the vendor's variable, it's a
 170                        Null-Terminated Unicode String
 171   @param  VendorGuid   Unify identifier for vendor.
 172   @param  Attributes   Point to memory location to return the attributes of variable. If the point
 173                        is NULL, the parameter would be ignored.
 174   @param  DataSize     As input, point to the maxinum size of return Data-Buffer.
 175                        As output, point to the actual size of the returned Data-Buffer.
 176   @param  Data         Point to return Data-Buffer.
 177
 178   @retval  EFI_SUCCESS            The function completed successfully.
 179   @retval  EFI_NOT_FOUND          The variable was not found.
 180   @retval  EFI_BUFFER_TOO_SMALL   The DataSize is too small for the result. DataSize has
 181                                   been updated with the size needed to complete the request.
 182   @retval  EFI_INVALID_PARAMETER  VariableName is NULL.
 183   @retval  EFI_INVALID_PARAMETER  VendorGuid is NULL.
 184   @retval  EFI_INVALID_PARAMETER  DataSize is NULL.
 185   @retval  EFI_INVALID_PARAMETER  The DataSize is not too small and Data is NULL.
 186   @retval  EFI_DEVICE_ERROR       The variable could not be retrieved due to a hardware error.
 187   @retval  EFI_SECURITY_VIOLATION The variable could not be retrieved due to an authentication failure.
 188 **/
 189 EFI_STATUS
 190 EFIAPI
 191 EfiGetVariable (
 192   IN      CHAR16                   *VariableName,
 193   IN      EFI_GUID                 *VendorGuid,
 194   OUT     UINT32                   *Attributes OPTIONAL,
 195   IN OUT  UINTN                    *DataSize,
 196   OUT     VOID                     *Data
 197   );
 198
 199 /**
 200   Enumerates variable's name.
 201
 202   @param  VariableNameSize As input, point to maxinum size of variable name.
 203                            As output, point to actual size of varaible name.
 204   @param  VariableName     As input, supplies the last VariableName that was returned by
 205                            GetNextVariableName().
 206                            As output, returns the name of variable. The name
 207                            string is Null-Terminated Unicode string.
 208   @param  VendorGuid       As input, supplies the last VendorGuid that was returned by
 209                            GetNextVriableName().
 210                            As output, returns the VendorGuid of the current variable.
 211
 212   @retval  EFI_SUCCESS           The function completed successfully.
 213   @retval  EFI_NOT_FOUND         The next variable was not found.
 214   @retval  EFI_BUFFER_TOO_SMALL  The VariableNameSize is too small for the result.
 215                                  VariableNameSize has been updated with the size needed
 216                                  to complete the request.
 217   @retval  EFI_INVALID_PARAMETER VariableNameSize is NULL.
 218   @retval  EFI_INVALID_PARAMETER VariableName is NULL.
 219   @retval  EFI_INVALID_PARAMETER VendorGuid is NULL.
 220   @retval  EFI_DEVICE_ERROR      The variable name could not be retrieved due to a hardware error.
 221
 222 **/
 223 EFI_STATUS
 224 EFIAPI
 225 EfiGetNextVariableName (
 226   IN OUT UINTN                    *VariableNameSize,
 227   IN OUT CHAR16                   *VariableName,
 228   IN OUT EFI_GUID                 *VendorGuid
 229   );
 230
 231 /**
 232   Sets value of variable.
 233
 234   @param  VariableName the name of the vendor's variable, it's a
 235                        Null-Terminated Unicode String
 236   @param  VendorGuid   Unify identifier for vendor.
 237   @param  Attributes   Point to memory location to return the attributes of variable. If the point
 238                        is NULL, the parameter would be ignored.
 239   @param  DataSize     The size in bytes of Data-Buffer.
 240   @param  Data         Point to the content of the variable.
 241
 242   @retval  EFI_SUCCESS            The firmware has successfully stored the variable and its data as
 243                                   defined by the Attributes.
 244   @retval  EFI_INVALID_PARAMETER  An invalid combination of attribute bits was supplied, or the
 245                                   DataSize exceeds the maximum allowed.
 246   @retval  EFI_INVALID_PARAMETER  VariableName is an empty Unicode string.
 247   @retval  EFI_OUT_OF_RESOURCES   Not enough storage is available to hold the variable and its data.
 248   @retval  EFI_DEVICE_ERROR       The variable could not be saved due to a hardware failure.
 249   @retval  EFI_WRITE_PROTECTED    The variable in question is read-only.
 250   @retval  EFI_WRITE_PROTECTED    The variable in question cannot be deleted.
 251   @retval  EFI_SECURITY_VIOLATION The variable could not be written due to EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS
 252                                   set but the AuthInfo does NOT pass the validation check carried
 253                                   out by the firmware.
 254   @retval  EFI_NOT_FOUND          The variable trying to be updated or deleted was not found.
 255
 256 **/
 257 EFI_STATUS
 258 EFIAPI
 259 EfiSetVariable (
 260   IN CHAR16                       *VariableName,
 261   IN EFI_GUID                     *VendorGuid,
 262   IN UINT32                       Attributes,
 263   IN UINTN                        DataSize,
 264   IN VOID                         *Data
 265   );
 266
 267 /**
 268   Returns the next high 32 bits of platform's monotonic counter.
 269
 270   @param  HighCount Pointer to returned value.
 271
 272   @retval  EFI_SUCCESS           The next high monotonic count was returned.
 273   @retval  EFI_DEVICE_ERROR      The device is not functioning properly.
 274   @retval  EFI_INVALID_PARAMETER HighCount is NULL.
 275
 276 **/
 277 EFI_STATUS
 278 EFIAPI
 279 EfiGetNextHighMonotonicCount (
 280   OUT UINT32                      *HighCount
 281   );
 282
 283 /**
 284   Resets the entire platform.
 285
 286   @param  ResetType   The type of reset to perform.
 287   @param  ResetStatus The status code for the reset. If the system reset is part of a
 288                       normal operation, the status code would be EFI_SUCCESS. If the system
 289                       reset is due to some type of failure the most appropriate EFI Status
 290                       code would be used.
 291   @param  DataSizeThe size, in bytes, of ResetData.
 292   @param  ResetData   For a ResetType of EfiResetCold, EfiResetWarm, or EfiResetShutdown
 293                       the data buffer starts with a Null-terminated Unicode string, optionally
 294                       followed by additional binary data. The string is a description that the
 295                       caller may use to further indicate the reason for the system reset. ResetData
 296                       is only valid if ResetStatus is something other then EFI_SUCCESS. This
 297                       pointer must be a physical address. For a ResetType of EfiRestUpdate the
 298                       data buffer also starts with a Null-terminated string that is followed by
 299                       a physical VOID * to an EFI_CAPSULE_HEADER.
 300
 301 **/
 302 VOID
 303 EFIAPI
 304 EfiResetSystem (
 305   IN EFI_RESET_TYPE               ResetType,
 306   IN EFI_STATUS                   ResetStatus,
 307   IN UINTN                        DataSize,
 308   IN CHAR16                       *ResetData
 309   );
 310
 311 /**
 312   This service converts a function pointer from physical to virtual addressing.
 313
 314   @param  DebugDisposition   Supplies type information for the pointer being converted.
 315   @param  Address            The pointer to a pointer that is to be fixed to be the
 316                              value needed for the new virtual address mapping being
 317                              applied.
 318
 319   @retval  EFI_SUCCESS            The pointer pointed to by Address was modified.
 320   @retval  EFI_NOT_FOUND          The pointer pointed to by Address was not found to be part of
 321                                   the current memory map. This is normally fatal.
 322   @retval  EFI_INVALID_PARAMETER  Address is NULL.
 323   @retval  EFI_INVALID_PARAMETER  *Address is NULL and DebugDispositio
 324
 325 **/
 326 EFI_STATUS
 327 EFIAPI
 328 EfiConvertPointer (
 329   IN UINTN                  DebugDisposition,
 330   IN OUT VOID               **Address
 331   );
 332
 333 /**
 334   Determines the new virtual address that is to be used on subsequent memory accesses.
 335
 336   For IA32, X64, and EBC, this service is a wrapper for the UEFI Runtime Service
 337   ConvertPointer().  See the UEFI Specification for details.
 338   For IPF, this function interprets Address as a pointer to an EFI_PLABEL structure
 339   and both the EntryPoint and GP fields of an EFI_PLABEL are converted from physical
 340   to virtiual addressing.  Since IPF allows the GP to point to an address outside
 341   a PE/COFF image, the physical to virtual offset for the EntryPoint field is used
 342   to adjust the GP field.  The UEFI Runtime Service ConvertPointer() is used to convert
 343   EntryPoint and the status code for this conversion is always returned.   If the convertion
 344   of EntryPoint fails, then neither EntryPoint nor GP are modified.  See the UEFI
 345   Specification for details on the UEFI Runtime Service ConvertPointer().
 346
 347   @param  DebugDisposition   Supplies type information for the pointer being converted.
 348   @param  Address            The pointer to a pointer that is to be fixed to be the
 349                              value needed for the new virtual address mapping being
 350                              applied.
 351
 352   @return  EFI_STATUS value from EfiConvertPointer().
 353
 354 **/
 355 EFI_STATUS
 356 EFIAPI
 357 EfiConvertFunctionPointer (
 358   IN UINTN                DebugDisposition,
 359   IN OUT VOID             **Address
 360   );
 361
 362 /**
 363   Change the runtime addressing mode of EFI firmware from physical to virtual.
 364
 365   @param  MemoryMapSize         The size in bytes of VirtualMap.
 366   @param  DescriptorSize        The size in bytes of an entry in the VirtualMap.
 367   @param  DescriptorVersion     The version of the structure entries in VirtualMap.
 368   @param  VirtualMap            An array of memory descriptors which contain new virtual
 369                                 address mapping information for all runtime ranges. Type
 370                                 EFI_MEMORY_DESCRIPTOR is defined in the
 371                                 GetMemoryMap() function description.
 372
 373   @retval EFI_SUCCESS           The virtual address map has been applied.
 374   @retval EFI_UNSUPPORTED       EFI firmware is not at runtime, or the EFI firmware is already in
 375                                 virtual address mapped mode.
 376   @retval EFI_INVALID_PARAMETER DescriptorSize or DescriptorVersion is
 377                                 invalid.
 378   @retval EFI_NO_MAPPING        A virtual address was not supplied for a range in the memory
 379                                 map that requires a mapping.
 380   @retval EFI_NOT_FOUND         A virtual address was supplied for an address that is not found
 381                                 in the memory map.
 382 **/
 383 EFI_STATUS
 384 EFIAPI
 385 EfiSetVirtualAddressMap (
 386   IN UINTN                          MemoryMapSize,
 387   IN UINTN                          DescriptorSize,
 388   IN UINT32                         DescriptorVersion,
 389   IN CONST EFI_MEMORY_DESCRIPTOR    *VirtualMap
 390   );
 391
 392
 393 /**
 394   Convert the standard Lib double linked list to a virtual mapping.
 395
 396   This service uses EfiConvertPointer() to walk a double linked list and convert all the link
 397   pointers to their virtual mappings. This function is only guaranteed to work during the
 398   EVT_SIGNAL_VIRTUAL_ADDRESS_CHANGE event and calling it at other times has undefined results.
 399
 400   @param  DebugDisposition   Supplies type information for the pointer being converted.
 401   @param  ListHead           Head of linked list to convert.
 402
 403   @retval  EFI_SUCCESS  Success to execute the function.
 404   @retval  !EFI_SUCCESS Failed to e3xecute the function.
 405
 406 **/
 407 EFI_STATUS
 408 EFIAPI
 409 EfiConvertList (
 410   IN UINTN                DebugDisposition,
 411   IN OUT LIST_ENTRY       *ListHead
 412   );
 413
 414 /**
 415   Passes capsules to the firmware with both virtual and physical mapping.
 416   Depending on the intended consumption, the firmware may
 417   process the capsule immediately. If the payload should persist across a
 418   system reset, the reset value returned from EFI_QueryCapsuleCapabilities must
 419   be passed into ResetSystem() and will cause the capsule to be processed by
 420   the firmware as part of the reset process.
 421
 422   @param  CapsuleHeaderArray    Virtual pointer to an array of virtual pointers to the capsules
 423                                 being passed into update capsule. Each capsules is assumed to
 424                                 stored in contiguous virtual memory. The capsules in the
 425                                 CapsuleHeaderArray must be the same capsules as the
 426                                 ScatterGatherList. The CapsuleHeaderArray must
 427                                 have the capsules in the same order as the ScatterGatherList.
 428   @param  CapsuleCount          Number of pointers to EFI_CAPSULE_HEADER in
 429                                 CaspuleHeaderArray.
 430   @param  ScatterGatherList     Physical pointer to a set of
 431                                 EFI_CAPSULE_BLOCK_DESCRIPTOR that describes the
 432                                 location in physical memory of a set of capsules. See Related
 433                                 Definitions for an explanation of how more than one capsule is
 434                                 passed via this interface. The capsules in the
 435                                 ScatterGatherList must be in the same order as the
 436                                 CapsuleHeaderArray. This parameter is only referenced if
 437                                 the capsules are defined to persist across system reset.
 438
 439   @retval EFI_SUCCESS           Valid capsule was passed. If CAPSULE_FLAGS_PERSIT_ACROSS_RESET is not set,
 440                                 the capsule has been successfully processed by the firmware.
 441   @retval EFI_INVALID_PARAMETER CapsuleSize or HeaderSize is NULL.
 442   @retval EFI_INVALID_PARAMETER CapsuleCount is 0
 443   @retval EFI_DEVICE_ERROR      The capsule update was started, but failed due to a device error.
 444   @retval EFI_UNSUPPORTED       The capsule type is not supported on this platform.
 445   @retval EFI_OUT_OF_RESOURCES  There were insufficient resources to process the capsule.
 446
 447 **/
 448 EFI_STATUS
 449 EFIAPI
 450 EfiUpdateCapsule (
 451   IN EFI_CAPSULE_HEADER       **CapsuleHeaderArray,
 452   IN UINTN                    CapsuleCount,
 453   IN EFI_PHYSICAL_ADDRESS     ScatterGatherList OPTIONAL
 454   );
 455
 456
 457 /**
 458   The QueryCapsuleCapabilities() function allows a caller to test to see if a capsule or
 459   capsules can be updated via UpdateCapsule(). The Flags values in the capsule header and
 460   size of the entire capsule is checked.
 461   If the caller needs to query for generic capsule capability a fake EFI_CAPSULE_HEADER can be
 462   constructed where CapsuleImageSize is equal to HeaderSize that is equal to sizeof
 463   (EFI_CAPSULE_HEADER). To determine reset requirements,
 464   CAPSULE_FLAGS_PERSIST_ACROSS_RESET should be set in the Flags field of the
 465   EFI_CAPSULE_HEADER.
 466   The firmware must support any capsule that has the
 467   CAPSULE_FLAGS_PERSIST_ACROSS_RESET flag set in EFI_CAPSULE_HEADER. The
 468   firmware sets the policy for what capsules are supported that do not have the
 469   CAPSULE_FLAGS_PERSIST_ACROSS_RESET flag set.
 470
 471   @param  CapsuleHeaderArray    Virtual pointer to an array of virtual pointers to the capsules
 472                                 being passed into update capsule. The capsules are assumed to
 473                                 stored in contiguous virtual memory.
 474   @param  CapsuleCount          Number of pointers to EFI_CAPSULE_HEADER in
 475                                 CaspuleHeaderArray.
 476   @param  MaximumCapsuleSize     On output the maximum size that UpdateCapsule() can
 477                                 support as an argument to UpdateCapsule() via
 478                                 CapsuleHeaderArray and ScatterGatherList.
 479                                 Undefined on input.
 480   @param  ResetType             Returns the type of reset required for the capsule update.
 481
 482   @retval EFI_SUCCESS           Valid answer returned.
 483   @retval EFI_INVALID_PARAMETER MaximumCapsuleSize is NULL.
 484   @retval EFI_UNSUPPORTED       The capsule type is not supported on this platform, and
 485                                 MaximumCapsuleSize and ResetType are undefined.
 486   @retval EFI_OUT_OF_RESOURCES  There were insufficient resources to process the query request.
 487
 488 **/
 489 EFI_STATUS
 490 EFIAPI
 491 EfiQueryCapsuleCapabilities (
 492   IN  EFI_CAPSULE_HEADER       **CapsuleHeaderArray,
 493   IN  UINTN                    CapsuleCount,
 494   OUT UINT64                   *MaximumCapsuleSize,
 495   OUT EFI_RESET_TYPE           *ResetType
 496   );
 497
 498
 499 /**
 500   Returns information about the EFI variables.
 501
 502   The QueryVariableInfo() function allows a caller to obtain the information about the
 503   maximum size of the storage space available for the EFI variables, the remaining size of the storage
 504   space available for the EFI variables and the maximum size of each individual EFI variable,
 505   associated with the attributes specified.
 506   The returned MaximumVariableStorageSize, RemainingVariableStorageSize,
 507   MaximumVariableSize information may change immediately after the call based on other
 508   runtime activities including asynchronous error events. Also, these values associated with different
 509   attributes are not additive in nature.
 510
 511   @param  Attributes            Attributes bitmask to specify the type of variables on
 512                                 which to return information. Refer to the
 513                                 GetVariable() function description.
 514   @param  MaximumVariableStorageSize
 515                                 On output the maximum size of the storage space
 516                                 available for the EFI variables associated with the
 517                                 attributes specified.
 518   @param  RemainingVariableStorageSize
 519                                 Returns the remaining size of the storage space
 520                                 available for the EFI variables associated with the
 521                                 attributes specified..
 522   @param  MaximumVariableSize   Returns the maximum size of the individual EFI
 523                                 variables associated with the attributes specified.
 524
 525   @retval EFI_SUCCESS           Valid answer returned.
 526   @retval EFI_INVALID_PARAMETER An invalid combination of attribute bits was supplied.
 527   @retval EFI_UNSUPPORTED       EFI_UNSUPPORTED The attribute is not supported on this platform, and the
 528                                 MaximumVariableStorageSize,
 529                                 RemainingVariableStorageSize, MaximumVariableSize
 530                                 are undefined.
 531 **/
 532 EFI_STATUS
 533 EFIAPI
 534 EfiQueryVariableInfo (
 535   IN UINT32   Attributes,
 536   OUT UINT64  *MaximumVariableStorageSize,
 537   OUT UINT64  *RemainingVariableStorageSize,
 538   OUT UINT64  *MaximumVariableSize
 539   );
 540
 541 #endif
 542