On 2021/11/10 下午7:27, Richard Henderson wrote:
> On 11/10/21 8:04 AM, LIU Zhiwei wrote:
>> Signed-off-by: LIU Zhiwei <zhiwei_liu@c-sky.com>
>> ---
>> target/riscv/csr.c | 5 ++---
>> target/riscv/insn_trans/trans_rvi.c.inc | 4 ++--
>> target/riscv/op_helper.c | 3 ++-
>> 3 files changed, 6 insertions(+), 6 deletions(-)
>>
>> diff --git a/target/riscv/csr.c b/target/riscv/csr.c
>> index 33e342f529..e07cd522ef 100644
>> --- a/target/riscv/csr.c
>> +++ b/target/riscv/csr.c
>> @@ -555,15 +555,14 @@ static RISCVException
>> write_mstatus(CPURISCVState *env, int csrno,
>> * RV32: MPV and GVA are not in mstatus. The current plan
>> is to
>> * add them to mstatush. For now, we just don't support it.
>> */
>> - mask |= MSTATUS_MPV | MSTATUS_GVA;
>> + mask |= MSTATUS_MPV | MSTATUS_GVA | MSTATUS64_UXL;
>> }
>> mstatus = (mstatus & ~mask) | (val & mask);
>> if (riscv_cpu_mxl(env) == MXL_RV64) {
>> - /* SXL and UXL fields are for now read only */
>> + /* SXL fields are for now read only */
>> mstatus = set_field(mstatus, MSTATUS64_SXL, MXL_RV64);
>> - mstatus = set_field(mstatus, MSTATUS64_UXL, MXL_RV64);
>> }
>> env->mstatus = mstatus;
>
> Why do you not allow writes to SXL?
That means we still don't support the change of SXLEN.
I didn't check the S-mode CSRs behavior when XLEN changes in this patch
set.
For example, the behavior of satp when trap into M-mode from S-mode if
SXLEN=32 and MXLEN=64.
>
> You're missing a change to write_sstatus to allow S-mode to write to UXL.
Yes.
>
>> diff --git a/target/riscv/insn_trans/trans_rvi.c.inc
>> b/target/riscv/insn_trans/trans_rvi.c.inc
>> index 7a0b037594..cb73a2f1ee 100644
>> --- a/target/riscv/insn_trans/trans_rvi.c.inc
>> +++ b/target/riscv/insn_trans/trans_rvi.c.inc
>> @@ -472,7 +472,7 @@ static bool trans_csrrw(DisasContext *ctx,
>> arg_csrrw *a)
>> return do_csrw(ctx, a->csr, src);
>> }
>> - TCGv mask = tcg_constant_tl(-1);
>> + TCGv mask = tcg_constant_tl(get_xl(ctx) == MXL_RV32 ? UINT32_MAX
>> : -1);
>> return do_csrrw(ctx, a->rd, a->csr, src, mask);
>> }
>> @@ -523,7 +523,7 @@ static bool trans_csrrwi(DisasContext *ctx,
>> arg_csrrwi *a)
>> return do_csrw(ctx, a->csr, src);
>> }
>> - TCGv mask = tcg_constant_tl(-1);
>> + TCGv mask = tcg_constant_tl(get_xl(ctx) == MXL_RV32 ? UINT32_MAX
>> : -1);
>> return do_csrrw(ctx, a->rd, a->csr, src, mask);
>> }
>> diff --git a/target/riscv/op_helper.c b/target/riscv/op_helper.c
>> index 095d39671b..561e156bec 100644
>> --- a/target/riscv/op_helper.c
>> +++ b/target/riscv/op_helper.c
>> @@ -50,7 +50,8 @@ target_ulong helper_csrr(CPURISCVState *env, int csr)
>> void helper_csrw(CPURISCVState *env, int csr, target_ulong src)
>> {
>> - RISCVException ret = riscv_csrrw(env, csr, NULL, src, -1);
>> + target_ulong mask = cpu_get_xl(env) == MXL_RV32 ? UINT32_MAX : -1;
>> + RISCVException ret = riscv_csrrw(env, csr, NULL, src, mask);
>> if (ret != RISCV_EXCP_NONE) {
>> riscv_raise_exception(env, ret, GETPC());
>>
>
> The rest of this should be a separate patch.
>
>
> r~