crypto: s390 - add System z hardware support for XTS mode

This patch adds System z hardware acceleration support for the AES XTS mode.
The hardware support is available beginning with System z196.

Signed-off-by: Jan Glauber <jang@linux.vnet.ibm.com>
Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 8 insertions, 14 deletions

diff --git a/drivers/crypto/Kconfig b/drivers/crypto/Kconfig
index 7957acbf76a2..78df36adbe6c 100644
--- a/drivers/crypto/Kconfig
+++ b/drivers/crypto/Kconfig
@@ -131,20 +131,14 @@ config CRYPTO_AES_S390
         select CRYPTO_BLKCIPHER
         help
           This is the s390 hardware accelerated implementation of the
-          AES cipher algorithms (FIPS-197). AES uses the Rijndael
-          algorithm.
-
-          Rijndael appears to be consistently a very good performer in
-          both hardware and software across a wide range of computing
-          environments regardless of its use in feedback or non-feedback
-          modes. Its key setup time is excellent, and its key agility is
-          good. Rijndael's very low memory requirements make it very well
-          suited for restricted-space environments, in which it also
-          demonstrates excellent performance. Rijndael's operations are
-          among the easiest to defend against power and timing attacks.
-
-          On s390 the System z9-109 currently only supports the key size
-          of 128 bit.
+          AES cipher algorithms (FIPS-197).
+
+          As of z9 the ECB and CBC modes are hardware accelerated
+          for 128 bit keys.
+          As of z10 the ECB and CBC modes are hardware accelerated
+          for all AES key sizes.
+          As of z196 the XTS mode is hardware accelerated for 256 and
+          512 bit keys.
 
 config S390_PRNG
         tristate "Pseudo random number generator device driver"