Like the implementation of AESNI/AVX, this patch adds an accelerated
implementation of AESNI/AVX2. In terms of code implementation, by
reusing AESNI/AVX mode-related codes, the amount of code is greatly
reduced. From the benchmark data, it can be seen that when the block
size is 1024, compared to AVX acceleration, the performance achieved
by AVX2 has increased by about 70%, it is also 7.7 times of the pure
software implementation of sm4-generic.

The main algorithm implementation comes from SM4 AES-NI work by
libgcrypt and Markku-Juhani O. Saarinen at:
https://github.com/mjosaarinen/sm4ni

This optimization supports the four modes of SM4, ECB, CBC, CFB,
and CTR. Since CBC and CFB do not support multiple block parallel
encryption, the optimization effect is not obvious.

Benchmark on Intel i5-6200U 2.30GHz, performance data of three
implementation methods, pure software sm4-generic, aesni/avx
acceleration, and aesni/avx2 acceleration, the data comes from
the 218 mode and 518 mode of tcrypt. The abscissas are blocks of
different lengths. The data is tabulated and the unit is Mb/s:

block-size  |    16      64     128     256    1024    1420    4096
sm4-generic
    ECB enc | 60.94   70.41   72.27   73.02   73.87   73.58   73.59
    ECB dec | 61.87   70.53   72.15   73.09   73.89   73.92   73.86
    CBC enc | 56.71   66.31   68.05   69.84   70.02   70.12   70.24
    CBC dec | 54.54   65.91   68.22   69.51   70.63   70.79   70.82
    CFB enc | 57.21   67.24   69.10   70.25   70.73   70.52   71.42
    CFB dec | 57.22   64.74   66.31   67.24   67.40   67.64   67.58
    CTR enc | 59.47   68.64   69.91   71.02   71.86   71.61   71.95
    CTR dec | 59.94   68.77   69.95   71.00   71.84   71.55   71.95
sm4-aesni-avx
    ECB enc | 44.95  177.35  292.06  316.98  339.48  322.27  330.59
    ECB dec | 45.28  178.66  292.31  317.52  339.59  322.52  331.16
    CBC enc | 57.75   67.68   69.72   70.60   71.48   71.63   71.74
    CBC dec | 44.32  176.83  284.32  307.24  328.61  312.61  325.82
    CFB enc | 57.81   67.64   69.63   70.55   71.40   71.35   71.70
    CFB dec | 43.14  167.78  282.03  307.20  328.35  318.24  325.95
    CTR enc | 42.35  163.32  279.11  302.93  320.86  310.56  317.93
    CTR dec | 42.39  162.81  278.49  302.37  321.11  310.33  318.37
sm4-aesni-avx2
    ECB enc | 45.19  177.41  292.42  316.12  339.90  322.53  330.54
    ECB dec | 44.83  178.90  291.45  317.31  339.85  322.55  331.07
    CBC enc | 57.66   67.62   69.73   70.55   71.58   71.66   71.77
    CBC dec | 44.34  176.86  286.10  501.68  559.58  483.87  527.46
    CFB enc | 57.43   67.60   69.61   70.52   71.43   71.28   71.65
    CFB dec | 43.12  167.75  268.09  499.33  558.35  490.36  524.73
    CTR enc | 42.42  163.39  256.17  493.95  552.45  481.58  517.19
    CTR dec | 42.49  163.11  256.36  493.34  552.62  481.49  516.83
Signed-off-by: Tianjia Zhang <tianjia.zhang@linux.alibaba.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>