Re: [PATCH 1/2] target/riscv: Add a function to refresh the dynamic CSRs xml.

[Tommy Wu]

Hi Alistair,
Thanks for the suggestion! Do you mean 

```

    ...

    g_free(cpu->dyn_csr_xml);
    riscv_gen_dynamic_csr_xml(cs, cpu-> gdb_num_regs  -  CSR_TABLE_SIZE);

    ...

``` ?

Or maybe we don't need this refresh function, and just add ext_ssaia & ext_smaia in the command line.

Best Regards,
Tommy

On Thu, May 25, 2023 at 10:33 AM Alistair Francis <alistair23@gmail.com> wrote:

On Tue, May 23, 2023 at 9:46 PM Tommy Wu <tommy.wu@sifive.com> wrote:
>
> When we change the cpu extension state after the cpu is
> realized, we cannot print the value of some CSRs in the remote
> gdb debugger. The root cause is that the dynamic CSR xml is
> generated when the cpu is realized.
>
> This patch add a function to refresh the dynamic CSR xml after
> the cpu is realized.
>
> Signed-off-by: Tommy Wu <tommy.wu@sifive.com>
> Reviewed-by: Frank Chang <frank.chang@sifive.com>
> ---
>  target/riscv/cpu.h     |  2 ++
>  target/riscv/gdbstub.c | 12 ++++++++++++
>  2 files changed, 14 insertions(+)
>
> diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
> index de7e43126a..dc8e592275 100644
> --- a/target/riscv/cpu.h
> +++ b/target/riscv/cpu.h
> @@ -494,6 +494,7 @@ struct ArchCPU {
>      CPUNegativeOffsetState neg;
>      CPURISCVState env;
>
> +    int dyn_csr_base_reg;
>      char *dyn_csr_xml;
>      char *dyn_vreg_xml;
>
> @@ -781,6 +782,7 @@ void riscv_get_csr_ops(int csrno, riscv_csr_operations *ops);
>  void riscv_set_csr_ops(int csrno, riscv_csr_operations *ops);
>
>  void riscv_cpu_register_gdb_regs_for_features(CPUState *cs);
> +void riscv_refresh_dynamic_csr_xml(CPUState *cs);
>
>  uint8_t satp_mode_max_from_map(uint32_t map);
>  const char *satp_mode_str(uint8_t satp_mode, bool is_32_bit);
> diff --git a/target/riscv/gdbstub.c b/target/riscv/gdbstub.c
> index 524bede865..9e97ee2c35 100644
> --- a/target/riscv/gdbstub.c
> +++ b/target/riscv/gdbstub.c
> @@ -230,6 +230,8 @@ static int riscv_gen_dynamic_csr_xml(CPUState *cs, int base_reg)
>          bitsize = 64;
>      }
>
> +    cpu->dyn_csr_base_reg = base_reg;
> +
>      g_string_printf(s, "<?xml version=\"1.0\"?>");
>      g_string_append_printf(s, "<!DOCTYPE feature SYSTEM \"gdb-target.dtd\">");
>      g_string_append_printf(s, "<feature name=\"org.gnu.gdb.riscv.csr\">");
> @@ -349,3 +351,13 @@ void riscv_cpu_register_gdb_regs_for_features(CPUState *cs)
>                                   "riscv-csr.xml", 0);
>      }
>  }
> +
> +void riscv_refresh_dynamic_csr_xml(CPUState *cs)
> +{
> +    RISCVCPU *cpu = RISCV_CPU(cs);
> +    if (!cpu->dyn_csr_xml) {
> +        g_assert_not_reached();
> +    }
> +    g_free(cpu->dyn_csr_xml);
> +    riscv_gen_dynamic_csr_xml(cs, cpu->dyn_csr_base_reg);

I don't really understand why we need dyn_csr_base_reg, could we just
use cs->gdb_num_regs directly here?

Alistair

> +}
> --
> 2.38.1
>
>