Re: [RFC PATCH v5 2/3] riscv: Introduce custom CSR hooks to riscv_csrrw()

[Richard Henderson]

On 10/22/21 1:34 AM, Ruinland ChuanTzu Tsai wrote:
> > > +    /* Custom CSR value holder per hart */
> > > +    void *custom_csr_val;
> > >    };
> >
> > Value singular?  Anyhow, I think that it's a mistake trying to hide the
> > value structure in another file.  It complicates allocation of the
> > CPURISCVState, and you have no mechanism by which to migrate the csr values.
>
> What I'm trying to do here is to provide a hook for CSR value storage and let
> it being set during CPU initilization. We have heterogeneous harts which
> have different sets of CSRs.

I understand that, but the common CPURISCVState should contain the storage for all of the 
CSRs for every possible hart.

I might have made a different call if we had a more object-y language, but we have C.  The 
difference in size (here exactly one word) is not worth the complication of splitting 
structures apart.


r~