[openssl/openssl] 79040c: S390x: Support ME and CRT offloading

[Juergen Christ]

  Branch: refs/heads/master
  Home:   https://github.com/openssl/openssl
  Commit: 79040cf29e011c21789563d74da626b7465a0540
      https://github.com/openssl/openssl/commit/79040cf29e011c21789563d74da626b7465a0540
  Author: Juergen Christ <jchrist at linux.ibm.com>
  Date:   2023-02-08 (Wed, 08 Feb 2023)

  Changed paths:
    A crypto/bn/bn_s390x.c
    M crypto/bn/build.info
    M crypto/dh/dh_key.c
    M crypto/rsa/rsa_ossl.c
    M crypto/s390x_arch.h
    M crypto/s390xcap.c
    M doc/man3/OPENSSL_s390xcap.pod
    M include/crypto/bn.h

  Log Message:
  -----------
  S390x: Support ME and CRT offloading

S390x has to ability to offload modular exponentiation and CRT operations to
Crypto Express Adapters.  This possible performance optimization was not yet
used by OpenSSL.  Add support for offloading and implement an optimized
version of RSA and DH with it.

The environment variable OPENSSL_s390xcap now recognizes the token "nocex" to
prevent offloading.

Signed-off-by: Juergen Christ <jchrist at linux.ibm.com>

Reviewed-by: Paul Dale <pauli at openssl.org>
Reviewed-by: Tomas Mraz <tomas at openssl.org>
(Merged from https://github.com/openssl/openssl/pull/20113)