[PATCH 1/5] config/riscv: add flag for using Zbc extension

[Stephen Hemminger]

On Tue, 18 Jun 2024 18:41:29 +0100
Daniel Gregory <daniel.gregory at bytedance.com> wrote:

> diff --git a/config/riscv/meson.build b/config/riscv/meson.build
> index 07d7d9da23..4bda4089bd 100644
> --- a/config/riscv/meson.build
> +++ b/config/riscv/meson.build
> @@ -26,6 +26,13 @@ flags_common = [
>      # read from /proc/device-tree/cpus/timebase-frequency. This property is
>      # guaranteed on Linux, as riscv time_init() requires it.
>      ['RTE_RISCV_TIME_FREQ', 0],
> +
> +    # Use RISC-V Carry-less multiplication extension (Zbc) for hardware
> +    # implementations of CRC-32C (lib/hash/rte_crc_riscv64.h), CRC-32 and CRC-16
> +    # (lib/net/net_crc_zbc.c). Requires intrinsics available in GCC 14.1.0+ and
> +    # Clang 18.1.0+
> +    # Make sure to add '_zbc' to your target's -march below
> +    ['RTE_RISCV_ZBC', false],
>  ]

Please do not add more config options via compile flags.
It makes it impossible for distros to ship one version.

Instead, detect at compile or runtime