[PATCH] Add trap-based ISA extension emulation

[Xiang W]

在 2025-10-26日的 21:21 +0100，Benedikt Freisen写道：
> This patch series seeks to add trap-based emulation functionality for various ISA extensions relevant to RVA22, RVB23 and RVA23.
> The emulation functionality contained herein has been demonstrated to e.g. allow the VisionFive 2's JH7110 to run software using the RVA22U64
> and RVB23U64 profiles, allow the Orange Pi RV2's Ky X1 (a SpacemiT K1 derivative) to run Ubuntu 25.10 (RVA23U64) in a docker container, and
> allow the Tenstorrent Blackhole's SiFive X280 (Gen. 1) to boot into Ubuntu 25.10.
> 
> The first patch merely fixes the tab alignment in riscv_encoding.h.
> 
> The second patch adds workarounds for decoder bugs in the C906 and C910, where FENCE and FENCE.I instructions with nonzero reserved fields are
> mistakenly treated as illegal instructions.
> 
> The third patch corrects the typedef of "s8" from "char" to "signed char", because "char" is implicitly unsigned on RISC-V.
> 
> To me, personally, these three look like uncontroversial improvements.
> 
> The fourth patch, the big one, adds the actual ISA extension emulation code.
> For initial consideration, I am hereby submitting it "as-is", mainly to see whether there is even interest in having this kind of
> functionality in mainline OpenSBI.
> If that turns out to be the case, this patch will need further iterations that, aside from incorporating your feedback, e.g. add configuration
> options for conditional compilation.
> 
> The fifth patch is included for documentary purposes only, not for merging.
> It contains the section of my fork's README file that explains which extensions can be emulated. The information therein could also go
> somewhere else.
> 
PATCH4 missing 

Regards,
Xiang W