[PATCH v2] eal/riscv: add Z sub-extension detection via hwprobe syscall

[Thomas Monjalon]

Hello,

We are waiting for a review of this patch.
The maintainer is Sun Yuechi.


23/03/2026 05:17, dangshiwei:
> The existing RISC-V rte_cpuflags implementation only detects
> single-letter ISA extensions (A, C, D, F, M, V, etc.) via
> AT_HWCAP. Z sub-extensions such as Zba, Zbb, Zbc, Zawrs and
> cryptography extensions (Zksed, Zksh, Zknd, Zkne) are not
> visible through AT_HWCAP and therefore cannot be used for
> runtime dispatch.
> 
> Linux 6.4 introduced the riscv_hwprobe syscall (NR 258) which
> exposes Z sub-extensions via the RISCV_HWPROBE_KEY_IMA_EXT_0
> key as a 64-bit bitmask. This patch adds support for querying
> Z sub-extensions through this interface.
> 
> Changes:
> - Add REG_HWPROBE_EXT0 source to cpu_register_t
> - Fix hwcap_registers_t type from uint32_t to uint64_t to
>   avoid truncation of AT_HWCAP on 64-bit platforms
> - Call riscv_hwprobe at EAL init via RTE_INIT and cache the
>   result; falls back silently on kernels older than 6.4
> - Add 56 new enum values for Z sub-extensions in rte_cpuflags.h
> - Extend cpuflags_autotest to cover all new flags
> 
> Signed-off-by: dangshiwei <1138222970gg at gmail.com>

Please could you separate you first and family names?

Thank you