Reinstate and export mpi_cmp() and mpi_cmp_ui() from the MPI library for use by
RSA signature verification as per RFC3447 section 5.2.2 step 1.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

This reverts commit 7e8dec91.

RSA verification implementation does not use this code.
James Morris has asked to remove that.
Signed-off-by: NDmitry Kasatkin <dmitry.kasatkin@intel.com>
Requested-by: NJames Morris <james.l.morris@oracle.com>
Signed-off-by: NJames Morris <james.l.morris@oracle.com>

Adds the multi-precision-integer maths library which was originally taken
from GnuPG and ported to the kernel by (among others) David Howells.
This version is taken from Fedora kernel 2.6.32-71.14.1.el6.
The difference is that checkpatch reported errors and warnings have been fixed.

This library is used to implemenet RSA digital signature verification
used in IMA/EVM integrity protection subsystem.

Due to patch size limitation, the patch is divided into 4 parts.

This code is unnecessary for RSA digital signature verification,
but for completeness it is included here and can be compiled,
if CONFIG_MPILIB_EXTRA is enabled.
Signed-off-by: NDmitry Kasatkin <dmitry.kasatkin@intel.com>