NAME

       OPENSSL_riscvcap - the RISC-V processor capabilities vector

SYNOPSIS

        env OPENSSL_riscvcap=... <application>

DESCRIPTION

       libcrypto supports RISC-V instruction set extensions. These extensions are denoted by individual
       extension names in the capabilities vector. For Linux platform, when libcrypto is initialized, the
       results returned by the RISC-V Hardware Probing syscall (hwprobe) are stored in the vector. Otherwise all
       capabilities are disabled.

       To override the set of instructions available to an application, you can set the OPENSSL_riscvcap
       environment variable before you start the application.

       The environment variable is similar to the RISC-V ISA string defined in the RISC-V Instruction Set
       Manual. It is case insensitive. Though due to the limit of the environment variable parser inside
       libcrypto, an extension must be prefixed with an underscore to make it recognizable. This also applies to
       the Vector extension.

        OPENSSL_riscvcap="rv64gc_v_zba_zbb_zbs..."

       Note that extension implication is currently not implemented.  For example, when "rv64gc_b" is provided
       as the environment variable, zba/zbb/zbs would not be implied in the capability vector.

       Currently only these extensions are recognized:

       ZBA Address Generation

           Could be detected using hwprobe for Linux kernel >= 6.5

       ZBB Basic bit-manipulation

           Could be detected using hwprobe for Linux kernel >= 6.5

       ZBC Carry-less multiplication

           Could be detected using hwprobe for Linux kernel >= 6.8

       ZBS Single-bit instructions

           Could be detected using hwprobe for Linux kernel >= 6.5

       ZBKB
           Bit-manipulation for Cryptography

           Could be detected using hwprobe for Linux kernel >= 6.8

       ZBKC
           Carry-less multiplication for Cryptography

           Could be detected using hwprobe for Linux kernel >= 6.8

       ZBKX
           Crossbar permutations

           Could be detected using hwprobe for Linux kernel >= 6.8

       ZKND
           NIST Suite: AES Decryption

           Could be detected using hwprobe for Linux kernel >= 6.8

       ZKNE
           NIST Suite: AES Encryption

           Could be detected using hwprobe for Linux kernel >= 6.8

       ZKNH
           NIST Suite: Hash Function Instructions

           Could be detected using hwprobe for Linux kernel >= 6.8

       ZKSED
           ShangMi Suite: SM4 Block Cipher Instructions

           Could be detected using hwprobe for Linux kernel >= 6.8

       ZKSH
           ShangMi Suite: SM3 Hash Function Instructions

           Could be detected using hwprobe for Linux kernel >= 6.8

       ZKR Entropy Source Extension

       ZKT Data Independent Execution Latency

           Could be detected using hwprobe for Linux kernel >= 6.8

       V   Vector Extension for Application Processors

           Could be detected using hwprobe for Linux kernel >= 6.5

       ZVBB
           Vector Basic Bit-manipulation

           Could be detected using hwprobe for Linux kernel >= 6.8

       ZVBC
           Vector Carryless Multiplication

           Could be detected using hwprobe for Linux kernel >= 6.8

       ZVKB
           Vector Cryptography Bit-manipulation

           Could be detected using hwprobe for Linux kernel >= 6.8

       ZVKG
           Vector GCM/GMAC

           Could be detected using hwprobe for Linux kernel >= 6.8

       ZVKNED
           NIST Suite: Vector AES Block Cipher

           Could be detected using hwprobe for Linux kernel >= 6.8

       ZVKNHA
           NIST Suite: Vector SHA-2 Secure Hash

           Could be detected using hwprobe for Linux kernel >= 6.8

       ZVKNHB
           NIST Suite: Vector SHA-2 Secure Hash

           Could be detected using hwprobe for Linux kernel >= 6.8

       ZVKSED
           ShangMi Suite: SM4 Block Cipher

           Could be detected using hwprobe for Linux kernel >= 6.8

       ZVKSH
           ShangMi Suite: SM3 Secure Hash

           Could be detected using hwprobe for Linux kernel >= 6.8

RETURN VALUES

       Not available.

EXAMPLES

       Check currently detected capabilities

        $ openssl info -cpusettings
        OPENSSL_riscvcap=ZBA_ZBB_ZBC_ZBS_V

       Disables all instruction set extensions:

        OPENSSL_riscvcap="rv64gc"

       Only enable the vector extension:

        OPENSSL_riscvcap="rv64gc_v"

COPYRIGHT

       Copyright 2024 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
       <https://www.openssl.org/source/license.html>.

3.4.1                                              2025-04-03                             OPENSSL_RISCVCAP(3SSL)