=pod

=head1 NAME

OPENSSL_s390xcap - the IBM z processor capabilities vector

=head1 SYNOPSIS

 env OPENSSL_s390xcap=... <application>

=head1 DESCRIPTION

libcrypto supports z/Architecture instruction set extensions. These
extensions are denoted by individual bits in the capabilities vector.
When libcrypto is initialized, the bits returned by the STFLE instruction
and by the QUERY functions are stored in the vector.

To change the set of instructions available to an application, you can
set the B<OPENSSL_s390xcap> environment variable before you start the
application. After initialization, the capability vector is ANDed bitwise
with a mask which is derived from the environment variable.

The environment variable is a semicolon-separated list of tokens which is
processed from left to right (whitespace is ignored):

 OPENSSL_s390xcap="<tok1>;<tok2>;..."

There are three types of tokens:

=over 4

=item <string>

The name of a processor generation. A bit in the environment variable's
mask is set to one if and only if the specified processor generation
implements the corresponding instruction set extension. Possible values
are B<z900>, B<z990>, B<z9>, B<z10>, B<z196>, B<zEC12>, B<z13>, B<z14>
and B<z15>.

=item <string>:<mask>:<mask>

The name of an instruction followed by two 64-bit masks. The part of the
environment variable's mask corresponding to the specified instruction is
set to the specified 128-bit mask. Possible values are B<kimd>, B<klmd>,
B<km>, B<kmc>, B<kmac>, B<kmctr>, B<kmo>, B<kmf>, B<prno>, B<kma>, B<pcc>
and B<kdsa>.

=item stfle:<mask>:<mask>:<mask>

Store-facility-list-extended (stfle) followed by three 64-bit masks. The
part of the environment variable's mask corresponding to the stfle
instruction is set to the specified 192-bit mask.

=back

The 64-bit masks are specified in hexadecimal notation. The 0x prefix is
optional. Prefix a mask with a tilde, C<~>, to denote a bitwise NOT operation.

The following is a list of significant bits for each instruction. Colon
rows separate the individual 64-bit masks. The bit numbers in the first
column are consistent with [1], that is, 0 denotes the leftmost bit and
the numbering is continuous across 64-bit mask boundaries.

      Bit     Mask     Facility/Function

 stfle:
      # 17    1<<46    message-security assist
      # 25    1<<38    store-clock-fast facility
      :
      # 76    1<<51    message-security assist extension 3
      # 77    1<<50    message-security assist extension 4
      :
      #129    1<<62    vector facility
      #134    1<<57    vector packed decimal facility
      #135    1<<56    vector enhancements facility 1
      #146    1<<45    message-security assist extension 8
      #155    1<<36    message-security assist extension 9

 kimd :
      #  1    1<<62    KIMD-SHA-1
      #  2    1<<61    KIMD-SHA-256
      #  3    1<<60    KIMD-SHA-512
      # 32    1<<31    KIMD-SHA3-224
      # 33    1<<30    KIMD-SHA3-256
      # 34    1<<29    KIMD-SHA3-384
      # 35    1<<28    KIMD-SHA3-512
      # 36    1<<27    KIMD-SHAKE-128
      # 37    1<<26    KIMD-SHAKE-256
      :
      # 65    1<<62    KIMD-GHASH

 klmd :
      # 32    1<<31    KLMD-SHA3-224
      # 33    1<<30    KLMD-SHA3-256
      # 34    1<<29    KLMD-SHA3-384
      # 35    1<<28    KLMD-SHA3-512
      # 36    1<<27    KLMD-SHAKE-128
      # 37    1<<26    KLMD-SHAKE-256
      :

 km   :
      # 18    1<<45    KM-AES-128
      # 19    1<<44    KM-AES-192
      # 20    1<<43    KM-AES-256
      # 50    1<<13    KM-XTS-AES-128
      # 52    1<<11    KM-XTS-AES-256
      :

 kmc  :
      # 18    1<<45    KMC-AES-128
      # 19    1<<44    KMC-AES-192
      # 20    1<<43    KMC-AES-256
      :

 kmac :
      # 18    1<<45    KMAC-AES-128
      # 19    1<<44    KMAC-AES-192
      # 20    1<<43    KMAC-AES-256
      :

 kmctr:
      :

 kmo  :
      # 18    1<<45    KMO-AES-128
      # 19    1<<44    KMO-AES-192
      # 20    1<<43    KMO-AES-256
      :

 kmf  :
      # 18    1<<45    KMF-AES-128
      # 19    1<<44    KMF-AES-192
      # 20    1<<43    KMF-AES-256
      :

 prno :
      :

 kma  :
      # 18    1<<45    KMA-GCM-AES-128
      # 19    1<<44    KMA-GCM-AES-192
      # 20    1<<43    KMA-GCM-AES-256
      :

 pcc  :
      :
      # 64    1<<63    PCC-Scalar-Multiply-P256
      # 65    1<<62    PCC-Scalar-Multiply-P384
      # 66    1<<61    PCC-Scalar-Multiply-P521
      # 72    1<<55    PCC-Scalar-Multiply-Ed25519
      # 73    1<<54    PCC-Scalar-Multiply-Ed448
      # 80    1<<47    PCC-Scalar-Multiply-X25519
      # 81    1<<46    PCC-Scalar-Multiply-X448

 kdsa :
      #  1    1<<62    KDSA-ECDSA-Verify-P256
      #  2    1<<61    KDSA-ECDSA-Verify-P384
      #  3    1<<60    KDSA-ECDSA-Verify-P521
      #  9    1<<54    KDSA-ECDSA-Sign-P256
      # 10    1<<53    KDSA-ECDSA-Sign-P384
      # 11    1<<52    KDSA-ECDSA-Sign-P521
      # 32    1<<31    KDSA-EdDSA-Verify-Ed25519
      # 36    1<<27    KDSA-EdDSA-Verify-Ed448
      # 40    1<<23    KDSA-EdDSA-Sign-Ed25519
      # 44    1<<19    KDSA-EdDSA-Sign-Ed448
      :

=head1 RETURN VALUES

Not available.

=head1 EXAMPLES

Disables all instruction set extensions which the z196 processor does not implement:

 OPENSSL_s390xcap="z196"

Disables the vector facility:

 OPENSSL_s390xcap="stfle:~0:~0:~0x4000000000000000"

Disables the KM-XTS-AES and and the KIMD-SHAKE function codes:

 OPENSSL_s390xcap="km:~0x2800:~0;kimd:~0xc000000:~0"

=head1 SEE ALSO

[1] z/Architecture Principles of Operation, SA22-7832-12

=head1 COPYRIGHT

Copyright 2018 The OpenSSL Project Authors. All Rights Reserved.

Licensed under the Apache License 2.0 (the "License").  You may not use
this file except in compliance with the License.  You can obtain a copy
in the file LICENSE in the source distribution or at
L<https://www.openssl.org/source/license.html>.

=cut
