2022-05-24 00:27:39

by Atish Kumar Patra

Subject: [PATCH v9 09/12] target/riscv: Simplify counter predicate function

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.

Reviewed-by: Bin Meng <[email protected]>
Acked-by: Alistair Francis <[email protected]>
Signed-off-by: Atish Patra <[email protected]>
---
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 723b52d836d3..e229f53c674d 100644
--- a/target/riscv/csr.c
+++ b/target/riscv/csr.c
@@ -74,6 +74,7 @@ static RISCVException ctr(CPURISCVState *env, int csrno)
CPUState *cs = env_cpu(env);
RISCVCPU *cpu = RISCV_CPU(cs);
int ctr_index;
+ target_ulong ctr_mask;
int base_csrno = CSR_CYCLE;
bool rv32 = riscv_cpu_mxl(env) == MXL_RV32 ? true : false;

@@ -82,122 +83,30 @@ 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;
}
}
#endif
--
2.25.1

2022-05-26 12:40:19

by Atish Patra

Subject: Re: [PATCH v9 09/12] target/riscv: Simplify counter predicate function

On Wed, May 25, 2022 at 3:24 AM Frank Chang <[email protected]> wrote:
>
> On Tue, May 24, 2022 at 8:02 AM Atish Patra <[email protected]> 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.
>>
>> Reviewed-by: Bin Meng <[email protected]>
>> Acked-by: Alistair Francis <[email protected]>
>> Signed-off-by: Atish Patra <[email protected]>
>> ---
>> 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 723b52d836d3..e229f53c674d 100644
>> --- a/target/riscv/csr.c
>> +++ b/target/riscv/csr.c
>> @@ -74,6 +74,7 @@ static RISCVException ctr(CPURISCVState *env, int csrno)
>> CPUState *cs = env_cpu(env);
>> RISCVCPU *cpu = RISCV_CPU(cs);
>> int ctr_index;
>> + target_ulong ctr_mask;
>> int base_csrno = CSR_CYCLE;
>> bool rv32 = riscv_cpu_mxl(env) == MXL_RV32 ? true : false;
>>
>> @@ -82,122 +83,30 @@ 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))) {
>
>
> Should we also check PRV_U against env->scounteren here?
>

Ahh yes. That's required while hpmcounter is being accessed from the
userspace. Good catch. Thanks. Will fix it.

> Regards,
> Frank Chang
>
>>
>> + 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;
>> }
>> }
>> #endif
>> --
>> 2.25.1
>>
>>


--
Regards,
Atish