Re: [PATCH v3 0/4] riscv: Separate vendor extensions from standard extensions

[Andrew Jones]

On Fri, Jul 19, 2024 at 09:15:17AM GMT, Charlie Jenkins wrote:
> All extensions, both standard and vendor, live in one struct
> "riscv_isa_ext". There is currently one vendor extension, xandespmu, but
> it is likely that more vendor extensions will be added to the kernel in
> the future. As more vendor extensions (and standard extensions) are
> added, riscv_isa_ext will become more bloated with a mix of vendor and
> standard extensions.

But the mix doesn't hurt and with everything in one place it makes it easy
to know where to look.

> 
> This also allows each vendor to be conditionally enabled through
> Kconfig.

We can do that anyway by adding an extension menu for each vendor. If we
don't want a vendor's extensions bloating the array then we just need
some #ifdefs, e.g.

@@ -405,7 +405,9 @@ const struct riscv_isa_ext_data riscv_isa_ext[] = {
        __RISCV_ISA_EXT_DATA(svinval, RISCV_ISA_EXT_SVINVAL),
        __RISCV_ISA_EXT_DATA(svnapot, RISCV_ISA_EXT_SVNAPOT),
        __RISCV_ISA_EXT_DATA(svpbmt, RISCV_ISA_EXT_SVPBMT),
+#ifdef RISCV_ISA_VENDOR_EXT_ANDES
        __RISCV_ISA_EXT_DATA(xandespmu, RISCV_ISA_EXT_XANDESPMU),
+#endif
 };


So, I'm not convinced we want the additional complexity of vendor
extension arrays, but maybe I'm missing something.

Thanks,
drew