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.