Intel Extensible Firmware Interface, Specification

Page: 94 / 494

Extensible Firmware Interface Specification
76 12/12/00 Version 1.02
3.4.6 ExitBootServices()
Summary
Terminates all boot services.
Prototype
EFI_STATUS
ExitBootServices (
IN EFI_HANDLE ImageHandle,
IN UINTN MapKey
);
Parameters
ImageHandle
Handle that identifies the exiting image. Type
EFI_HANDLE
is defined
in Section 3.3.1.
MapKey
Key to the latest memory map.
Description
The
ExitBootServices()
function is called by the currently executing EFI OS loader image
to terminate all boot services. On success, the loader becomes responsible for the continued
operation of the system.
An EFI OS loader must ensure that it has the system’s current memory map at the time it calls
ExitBootServices()
. This is done by passing in the current memory map’s
MapKey
value
as returned by
GetMemoryMap()
. Care must be taken to ensure that the memory map does not
change between these two calls. It is suggested that
GetMemoryMap()
be called immediately
before calling
ExitBootServices()
.
On success, the EFI OS loader owns all available memory in the system. In addition, the loader can
treat all memory in the map marked as
EfiBootServicesCode
and
EfiBootServicesData
as available free memory. No further calls to boot service functions or
EFI device-handle-based protocols may be used, and the boot serviceswatchdog timer is disabled.
Status Codes Returned
EFI_SUCCESS Boot services have been terminated.
EFI_INVALID_PARAMETER
MapKey
is incorrect.