Re: [PATCH v4 09/11] target/riscv: Simplify counter predicate function

[Atish Kumar Patra <atishp@rivosinc.com>]

On Mon, Jan 10, 2022 at 12:27 AM Bin Meng <bmeng.cn@gmail.com> wrote:
>
> On Fri, Jan 7, 2022 at 10:22 AM Atish Patra <atishp@rivosinc.com> wrote:
> >
> > All the hpmcounters and the fixed counters (CY, IR, TM) can be represented
> > as a unified counter. Thus, the predicate function doesn't need handle each
> > case separately.
> >
> > Simplify the predicate function so that we just handle things differently
> > between RV32/RV64 and S/HS mode.
> >
> > Signed-off-by: Atish Patra <atishp@rivosinc.com>
> > ---
> >  target/riscv/csr.c | 111 ++++-----------------------------------------
> >  1 file changed, 10 insertions(+), 101 deletions(-)
> >
> > diff --git a/target/riscv/csr.c b/target/riscv/csr.c
> > index d3a8bba6a518..feb053eb3f7b 100644
> > --- a/target/riscv/csr.c
> > +++ b/target/riscv/csr.c
> > @@ -109,6 +109,7 @@ static RISCVException ctr(CPURISCVState *env, int csrno)
> >      CPUState *cs = env_cpu(env);
> >      RISCVCPU *cpu = RISCV_CPU(cs);
> >      int ctr_index;
> > +    uint64_t ctr_mask;
>
> Use target_ulong should be enough?
>

Yeah. Will fix it in the next version.

> >      int base_csrno = CSR_CYCLE;
> >      bool rv32 = riscv_cpu_mxl(env) == MXL_RV32 ? true : false;
> >
> > @@ -117,122 +118,30 @@ static RISCVException ctr(CPURISCVState *env, int csrno)
> >          base_csrno += 0x80;
> >      }
> >      ctr_index = csrno - base_csrno;
> > +    ctr_mask = BIT(ctr_index);
> >
> >      if ((csrno >= CSR_CYCLE && csrno <= CSR_INSTRET) ||
> >          (csrno >= CSR_CYCLEH && csrno <= CSR_INSTRETH)) {
> >          goto skip_ext_pmu_check;
> >      }
> >
> > -    if ((!cpu->cfg.pmu_num || !(cpu->pmu_avail_ctrs & BIT(ctr_index)))) {
> > +    if ((!cpu->cfg.pmu_num || !(cpu->pmu_avail_ctrs & ctr_mask))) {
> >          /* No counter is enabled in PMU or the counter is out of range */
> >          return RISCV_EXCP_ILLEGAL_INST;
> >      }
> >
> >  skip_ext_pmu_check:
> >
> > -    if (env->priv == PRV_S) {
> > -        switch (csrno) {
> > -        case CSR_CYCLE:
> > -            if (!get_field(env->mcounteren, COUNTEREN_CY)) {
> > -                return RISCV_EXCP_ILLEGAL_INST;
> > -            }
> > -            break;
> > -        case CSR_TIME:
> > -            if (!get_field(env->mcounteren, COUNTEREN_TM)) {
> > -                return RISCV_EXCP_ILLEGAL_INST;
> > -            }
> > -            break;
> > -        case CSR_INSTRET:
> > -            if (!get_field(env->mcounteren, COUNTEREN_IR)) {
> > -                return RISCV_EXCP_ILLEGAL_INST;
> > -            }
> > -            break;
> > -        case CSR_HPMCOUNTER3...CSR_HPMCOUNTER31:
> > -            if (!get_field(env->mcounteren, 1 << ctr_index)) {
> > -                return RISCV_EXCP_ILLEGAL_INST;
> > -            }
> > -            break;
> > -        }
> > -        if (rv32) {
> > -            switch (csrno) {
> > -            case CSR_CYCLEH:
> > -                if (!get_field(env->mcounteren, COUNTEREN_CY)) {
> > -                    return RISCV_EXCP_ILLEGAL_INST;
> > -                }
> > -                break;
> > -            case CSR_TIMEH:
> > -                if (!get_field(env->mcounteren, COUNTEREN_TM)) {
> > -                    return RISCV_EXCP_ILLEGAL_INST;
> > -                }
> > -                break;
> > -            case CSR_INSTRETH:
> > -                if (!get_field(env->mcounteren, COUNTEREN_IR)) {
> > -                    return RISCV_EXCP_ILLEGAL_INST;
> > -                }
> > -                break;
> > -            case CSR_HPMCOUNTER3H...CSR_HPMCOUNTER31H:
> > -                if (!get_field(env->mcounteren, 1 << ctr_index)) {
> > -                    return RISCV_EXCP_ILLEGAL_INST;
> > -                }
> > -                break;
> > -            }
> > -        }
> > +    if ((env->priv == PRV_S) && (!get_field(env->mcounteren, ctr_mask))) {
> > +        return RISCV_EXCP_ILLEGAL_INST;
> >      }
> >
> >      if (riscv_cpu_virt_enabled(env)) {
> > -        switch (csrno) {
> > -        case CSR_CYCLE:
> > -            if (!get_field(env->hcounteren, COUNTEREN_CY) &&
> > -                get_field(env->mcounteren, COUNTEREN_CY)) {
> > -                return RISCV_EXCP_VIRT_INSTRUCTION_FAULT;
> > -            }
> > -            break;
> > -        case CSR_TIME:
> > -            if (!get_field(env->hcounteren, COUNTEREN_TM) &&
> > -                get_field(env->mcounteren, COUNTEREN_TM)) {
> > -                return RISCV_EXCP_VIRT_INSTRUCTION_FAULT;
> > -            }
> > -            break;
> > -        case CSR_INSTRET:
> > -            if (!get_field(env->hcounteren, COUNTEREN_IR) &&
> > -                get_field(env->mcounteren, COUNTEREN_IR)) {
> > -                return RISCV_EXCP_VIRT_INSTRUCTION_FAULT;
> > -            }
> > -            break;
> > -        case CSR_HPMCOUNTER3...CSR_HPMCOUNTER31:
> > -            if (!get_field(env->hcounteren, 1 << ctr_index) &&
> > -                 get_field(env->mcounteren, 1 << ctr_index)) {
> > -                return RISCV_EXCP_VIRT_INSTRUCTION_FAULT;
> > -            }
> > -            break;
> > -        }
> > -        if (rv32) {
> > -            switch (csrno) {
> > -            case CSR_CYCLEH:
> > -                if (!get_field(env->hcounteren, COUNTEREN_CY) &&
> > -                    get_field(env->mcounteren, COUNTEREN_CY)) {
> > -                    return RISCV_EXCP_VIRT_INSTRUCTION_FAULT;
> > -                }
> > -                break;
> > -            case CSR_TIMEH:
> > -                if (!get_field(env->hcounteren, COUNTEREN_TM) &&
> > -                    get_field(env->mcounteren, COUNTEREN_TM)) {
> > -                    return RISCV_EXCP_VIRT_INSTRUCTION_FAULT;
> > -                }
> > -                break;
> > -            case CSR_INSTRETH:
> > -                if (!get_field(env->hcounteren, COUNTEREN_IR) &&
> > -                    get_field(env->mcounteren, COUNTEREN_IR)) {
> > -                    return RISCV_EXCP_VIRT_INSTRUCTION_FAULT;
> > -                }
> > -                break;
> > -            case CSR_HPMCOUNTER3H...CSR_HPMCOUNTER31H:
> > -                if (!get_field(env->hcounteren, 1 << ctr_index) &&
> > -                     get_field(env->mcounteren, 1 << ctr_index)) {
> > -                    return RISCV_EXCP_VIRT_INSTRUCTION_FAULT;
> > -                }
> > -                break;
> > -            }
> > +        if (!get_field(env->mcounteren, ctr_mask)) {
> > +            /* The bit must be set in mcountern for HS mode access */
> > +            return RISCV_EXCP_VIRT_INSTRUCTION_FAULT;
> > +        } else if (!get_field(env->hcounteren, ctr_mask)) {
> > +            return RISCV_EXCP_VIRT_INSTRUCTION_FAULT;
> >          }
> >      }
>
> Reviewed-by: Bin Meng <bmeng.cn@gmail.com>