Skip to content

OPENSSL_riscvcap

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 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.