PCLMULQDQ is used to accelerate the most time-consuming part of GHASH,
carry-less multiplication. More information about PCLMULQDQ can be
found at:

http://software.intel.com/en-us/articles/carry-less-multiplication-and-its-usage-for-computing-the-gcm-mode/

Because PCLMULQDQ changes XMM state, its usage must be enclosed with
kernel_fpu_begin/end, which can be used only in process context, the
acceleration is implemented as crypto_ahash. That is, request in soft
IRQ context will be defered to the cryptd kernel thread.
Signed-off-by: NHuang Ying <ying.huang@intel.com>
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

cryptd_alloc_ahash() will allocate a cryptd-ed ahash for specified
algorithm name. The new allocated one is guaranteed to be cryptd-ed
ahash, so the shash underlying can be gotten via cryptd_ahash_child().
Signed-off-by: NHuang Ying <ying.huang@intel.com>
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

cryptd_alloc_ablkcipher() will allocate a cryptd-ed ablkcipher for
specified algorithm name. The new allocated one is guaranteed to be
cryptd-ed ablkcipher, so the blkcipher underlying can be gotten via
cryptd_ablkcipher_child().
Signed-off-by: NHuang Ying <ying.huang@intel.com>
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>