Re: [PATCH v4 2/4] target/riscv/pmp.c: Fix the index offset on RV64

[Zong Li]

On Fri, Jul 24, 2020 at 5:22 PM Bin Meng <bmeng.cn@gmail.com> wrote:
>
> Hi Zong,
>
> On Fri, Jul 24, 2020 at 5:08 PM Zong Li <zong.li@sifive.com> wrote:
> >
> > On RV64, the reg_index is 2 (pmpcfg2 CSR) after the seventh pmp
> > entry, it is not 1 (pmpcfg1 CSR) like RV32. In the original
> > implementation, the second parameter of pmp_write_cfg is
> > "reg_index * sizeof(target_ulong)", and we get the the result
> > which is started from 16 if reg_index is 2, but we expect that
> > it should be started from 8. Separate the implementation for
> > RV32 and RV64 respectively.
> >
> > Signed-off-by: Zong Li <zong.li@sifive.com>
> > ---
> >  target/riscv/pmp.c | 8 ++++++++
> >  1 file changed, 8 insertions(+)
> >
> > diff --git a/target/riscv/pmp.c b/target/riscv/pmp.c
> > index 2a2b9f5363..e0161d6aab 100644
> > --- a/target/riscv/pmp.c
> > +++ b/target/riscv/pmp.c
> > @@ -310,6 +310,10 @@ void pmpcfg_csr_write(CPURISCVState *env, uint32_t 
> > reg_index,
> >      int i;
> >      uint8_t cfg_val;
> >
> > +#if defined(TARGET_RISCV64)
> > +    reg_index >>= 1;
> > +#endif
> > +
> >      trace_pmpcfg_csr_write(env->mhartid, reg_index, val);
> >
> >      if ((reg_index & 1) && (sizeof(target_ulong) == 8)) {
> > @@ -335,6 +339,10 @@ target_ulong pmpcfg_csr_read(CPURISCVState *env, 
> > uint32_t reg_index)
> >      target_ulong cfg_val = 0;
> >      target_ulong val = 0;
> >
> > +#if defined(TARGET_RISCV64)
> > +    reg_index >>= 1;
> > +#endif
> > +
> >      for (i = 0; i < sizeof(target_ulong); i++) {
> >          val = pmp_read_cfg(env, (reg_index * sizeof(target_ulong)) + i);
> >          cfg_val |= (val << (i * 8));
> > --
>
> It seems you missed to address my review comments in v3? reg_index
> should be shifted after we call the trace function.
>

Sorry for that, there was something wrong in my local tree, I have
been posting the 5th version patches, and hope it picks the suggestion
already. Thanks.

> Regards,
> Bin