Intel Extensible Firmware Interface, Specification

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Services
Version 1.02 12/12/00 75
When an EFI application exits, firmware frees the memory used to hold the image. The firmware
also frees its references to the
ImageHandle
and the handle itself. Before exiting, the application
is responsible for freeing any resources it allocated. This includes memory (pages and/or pool),
open file system handles, and so forth. The only exception to this rule is the
ExitData
buffer,
which must be freed by the caller of
StartImage()
. (If the buffer is needed, firmware must
allocate it by calling
AllocatePool()
and must return a pointer to it to the caller of
StartImage()
.)
When an EFI boot service driver or runtime service driver exits, firmware frees the image only if
the
ExitStatus
is an error code; otherwise the image stays resident in memory. The driver must
not return an error code if it has installed any protocol handlers or other active callouts into the
system that have not (or cannot) be cleaned up. If the driver exits with an error code, it is
responsible for freeing all resources before exiting. This includes any allocated memory (pages
and/or pool), open file system handles, and so forth.
It is valid to call
Exit()
or
Unload()
for an image that was loaded by
LoadImage()
before
calling
StartImage()
. This will free the image from memory without having started it.
Status Codes Returned
(Does not return.)
Image exit. Control is returned from the
StartImage()
call that
invoked the image.
EFI_SUCCESS
The image was unloaded.
Exit()
only returns success if the
image has not been started; otherwise, the exit returns to the
StartImage()
call that invoked the image.
EFI_INVALID_PARAMETER The specified image is not the current image.