s390: introduce .boot.preserved.data section

Introduce .boot.preserve.data section which is similar to .boot.data and
"shared" between the decompressor code and the decompressed kernel. The
decompressor will store values in it, and copy over to the decompressed
image before starting it. This method allows to avoid using pre-defined
addresses and other hacks to pass values between those boot phases.

Unlike .boot.data section .boot.preserved.data is NOT a part of init data,
and hence will be preserved for the kernel life time.

Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390: introduce .boot.data section

Introduce .boot.data section which is "shared" between the decompressor
code and the decompressed kernel. The decompressor will store values in
it, and copy over to the decompressed image before starting it. This
method allows to avoid using pre-defined addresses and other hacks to
pass values between those boot phases.

.boot.data section is a part of init data, and will be freed after kernel
initialization is complete.

For uncompressed kernel image, .boot.data section is basically the same
as .init.data

Reviewed-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>