Re: [PATCH] target/riscv: Add User CSRs read-only check

[LIU Zhiwei]

On 2021/8/9 下午5:35, Bin Meng wrote:
> On Mon, Aug 9, 2021 at 3:09 PM LIU Zhiwei <zhiwei_liu@c-sky.com> wrote:
> nits: please write something in the commit message
OK
> > Signed-off-by: LIU Zhiwei <zhiwei_liu@c-sky.com>
> > ---
> >   target/riscv/csr.c | 6 +++++-
> >   1 file changed, 5 insertions(+), 1 deletion(-)
> >
> > diff --git a/target/riscv/csr.c b/target/riscv/csr.c
> > index 9a4ed18ac5..ea62d9e653 100644
> > --- a/target/riscv/csr.c
> > +++ b/target/riscv/csr.c
> > @@ -1422,11 +1422,11 @@ RISCVException riscv_csrrw(CPURISCVState *env, int 
> > csrno,
> >       RISCVException ret;
> >       target_ulong old_value;
> >       RISCVCPU *cpu = env_archcpu(env);
> > +    int read_only = get_field(csrno, 0xC00) == 3;
> >
> >       /* check privileges and return -1 if check fails */
> >   #if !defined(CONFIG_USER_ONLY)
> >       int effective_priv = env->priv;
> > -    int read_only = get_field(csrno, 0xC00) == 3;
> >
> >       if (riscv_has_ext(env, RVH) &&
> >           env->priv == PRV_S &&
> > @@ -1443,6 +1443,10 @@ RISCVException riscv_csrrw(CPURISCVState *env, int csrno,
> >           (!env->debugger && (effective_priv < get_field(csrno, 0x300)))) {
> >           return RISCV_EXCP_ILLEGAL_INST;
> >       }
> > +#else
> > +    if (write_mask && read_only) {
> This can be merged by the !CONFIG_USER_ONLY case.

Do you mean

#if !defined(CONFIG_USER_ONLY)
     if (!env->debugger && (effective_priv < get_field(csrno, 0x300))) {
         return -RISCV_EXCP_ILLEGAL_INST;
}
#else
     if (write_mask && read_only) {
         return -RISCV_EXCP_ILLEGAL_INST;
}

#endif


Thanks,
Zhiwei

> > +        return -RISCV_EXCP_ILLEGAL_INST;
> > +    }
> >   #endif
> >
> >       /* ensure the CSR extension is enabled. */
> Regards,
> Bin