Re: [PATCH] target/riscv: csr: Implement mconfigptr CSR

[Rahul Pathak]

Hi Bin


On Thu, Oct 7, 2021 at 11:07 AM Bin Meng <bmeng.cn@gmail.com> wrote:
>
> On Sun, Oct 3, 2021 at 7:29 PM Rahul Pathak <rpathak@ventanamicro.com> wrote:
> >
> > mconfigptr is an mandatory CSR as per the priv spec.
>
> %s/an/a
>

Done

>
> as per the priv spec v1.12
>
> > This csr holds the physical address of the configuration
> > data structure if this data structure is implemented
> > Its an readonly csr set to zero making configuration
> > data structure not supported.
> >
> > Signed-off-by: Rahul Pathak <rpathak@ventanamicro.com>
> > ---
> >  target/riscv/cpu_bits.h | 1 +
> >  target/riscv/csr.c      | 1 +
> >  2 files changed, 2 insertions(+)
> >
> > diff --git a/target/riscv/cpu_bits.h b/target/riscv/cpu_bits.h
> > index 999187a9ee..5dc4729ed5 100644
> > --- a/target/riscv/cpu_bits.h
> > +++ b/target/riscv/cpu_bits.h
> > @@ -140,6 +140,7 @@
> >  #define CSR_MARCHID         0xf12
> >  #define CSR_MIMPID          0xf13
> >  #define CSR_MHARTID         0xf14
> > +#define CSR_MCONFIGPTR      0xf15
> >
> >  /* Machine Trap Setup */
> >  #define CSR_MSTATUS         0x300
> > diff --git a/target/riscv/csr.c b/target/riscv/csr.c
> > index 23fbbd3216..2182943f54 100644
> > --- a/target/riscv/csr.c
> > +++ b/target/riscv/csr.c
> > @@ -1549,6 +1549,7 @@ riscv_csr_operations csr_ops[CSR_TABLE_SIZE] = {
> >      [CSR_MARCHID]   = { "marchid",   any,   read_zero    },
> >      [CSR_MIMPID]    = { "mimpid",    any,   read_zero    },
> >      [CSR_MHARTID]   = { "mhartid",   any,   read_mhartid },
> > +    [CSR_MCONFIGPTR] = {"mconfigptr", any,  read_zero    },
>
> Not any, as we need to check the priv version >= 1.12


To check the priv version, I am thinking of creating a generic
predicate function
which checks the env->priv_ver.?
Generic predicate function for the priv version can be reused in other such
scenarios also.


>
> >
> >      /* Machine Trap Setup */
> >      [CSR_MSTATUS]     = { "mstatus",    any,   read_mstatus,     
> > write_mstatus     },
> > --
>
> Regards,
> Bin