[PATCH v1 1/1] riscv: Add RVV memset via multiarch/IFUNC

[Darius Rad]

On Thu, Oct 30, 2025 at 12:10:22AM +0800, Yao Zihong wrote:
> This patch adds an RVV-optimized implementation of memset for RISC-V and
> enables it through the existing multiarch/IFUNC mechanism.
> 
> The implementation integrates Hau Hsu’s 2023 RVV work under a unified
> ifunc-based framework. A vectorized version (__memset_vector) is added
> alongside the generic fallback (__memset_generic). The runtime resolver
> selects the RVV variant when RISCV_HWPROBE_KEY_IMA_EXT_0 reports vector
> support (V).
> 

This needs to use dl_hwcap, not hwprobe, to decide whether to select vector
or not, since vector may be present but not enabled (by prctl).