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

Commit Message

Tommy Wu May 23, 2023, 11:44 a.m. UTC

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 <[e-mail]>
Reviewed-by: Frank Chang <[e-mail]>
---
 target/riscv/cpu.h     |  2 ++
 target/riscv/gdbstub.c | 12 ++++++++++++
 2 files changed, 14 insertions(+)

Comments

Weiwei Li May 23, 2023, 2:37 p.m. UTC | #1

On 2023/5/23 19:44, Tommy Wu 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 <[e-mail]>
> Reviewed-by: Frank Chang <[e-mail]>
> ---
>   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;

dyn_csr_base_reg  seems have no additional effect on the function.

And It remains unmodified in following riscv_refresh_dynamic_csr_xml().

Regards,

Weiwei Li

>       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);
> +}

Tommy Wu May 24, 2023, 1:59 a.m. UTC | #2

Hi Weiwei Li,

`dyn_csr_base_reg` will be used in `riscv_refresh_dynamic_csr_xml`
We can initialize this variable when the cpu is realized. And used this
variable in `riscv_refresh_dynamic_csr_xml`.

Best regards,
Tommy


On Tue, May 23, 2023 at 10:38 PM Weiwei Li <[e-mail]> wrote:

>
> On 2023/5/23 19:44, Tommy Wu 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 <[e-mail]>
> > Reviewed-by: Frank Chang <[e-mail]>
> > ---
> >   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;
>
> dyn_csr_base_reg  seems have no additional effect on the function.
>
> And It remains unmodified in following riscv_refresh_dynamic_csr_xml().
>
> Regards,
>
> Weiwei Li
>
> >       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);
> > +}
>
>

Weiwei Li May 24, 2023, 2:10 a.m. UTC | #3

On 2023/5/24 09:59, Tommy Wu wrote:
> Hi Weiwei Li,
>
> `dyn_csr_base_reg` will be used in `riscv_refresh_dynamic_csr_xml`
> We can initialize this variable when the cpu is realized.
I didn't find this initialization in following code.
> And used this variable in `riscv_refresh_dynamic_csr_xml`.

That's my question. In riscv_refresh_dynamic_csr_xml() , 
cpu->dyn_csr_base_reg is passed to riscv_gen_dynamic_csr_xml() as base_reg.

And then base_reg is assigned to cpu->dyn_csr_base_reg again in it. So 
it's unchanged in this progress.

Another question is  dyn_csr_base_reg seems have no additional function 
currently.

Regards,

Weiwei Li

>
> Best regards,
> Tommy
>
>
> On Tue, May 23, 2023 at 10:38 PM Weiwei Li <[e-mail]> wrote:
>
>
>     On 2023/5/23 19:44, Tommy Wu 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 <[e-mail]>
>     > Reviewed-by: Frank Chang <[e-mail]>
>     > ---
>     >   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;
>
>     dyn_csr_base_reg  seems have no additional effect on the function.
>
>     And It remains unmodified in following
>     riscv_refresh_dynamic_csr_xml().
>
>     Regards,
>
>     Weiwei Li
>
>     >       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);
>     > +}
>

Tommy Wu May 24, 2023, 5:35 a.m. UTC | #4

Hi WeiWei Li,


When the CPU is realizing, it will call `riscv_gen_dynamic_csr_xml` for the
first time with the correct `base_reg` value.

code flow :

riscv_cpu_realize

→ riscv_cpu_register_gdb_regs_for_features

     → riscv_gen_dynamic_csr_xml

The functionality of `cpu->dyn_csr_base_reg` is to record the `base_reg`
from

`riscv_cpu_register_gdb_regs_for_features`.

When we try to refresh the dynamic CSRs xml, we will call the function
`riscv_gen_dynamic_csr_xml`

for the second time, and then we can give the correct `base_reg` value to
the function

`riscv_gen_dynamic_csr_xml`, because we've record this value in the `
cpu->dyn_csr_base_reg`.

Best Regards,

Tommy


On Wed, May 24, 2023 at 10:10 AM Weiwei Li <[e-mail]> wrote:

>
> On 2023/5/24 09:59, Tommy Wu wrote:
> > Hi Weiwei Li,
> >
> > `dyn_csr_base_reg` will be used in `riscv_refresh_dynamic_csr_xml`
> > We can initialize this variable when the cpu is realized.
> I didn't find this initialization in following code.
> > And used this variable in `riscv_refresh_dynamic_csr_xml`.
>
> That's my question. In riscv_refresh_dynamic_csr_xml() ,
> cpu->dyn_csr_base_reg is passed to riscv_gen_dynamic_csr_xml() as base_reg.
>
> And then base_reg is assigned to cpu->dyn_csr_base_reg again in it. So
> it's unchanged in this progress.
>
> Another question is  dyn_csr_base_reg seems have no additional function
> currently.
>
> Regards,
>
> Weiwei Li
>
> >
> > Best regards,
> > Tommy
> >
> >
> > On Tue, May 23, 2023 at 10:38 PM Weiwei Li <[e-mail]> wrote:
> >
> >
> >     On 2023/5/23 19:44, Tommy Wu 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 <[e-mail]>
> >     > Reviewed-by: Frank Chang <[e-mail]>
> >     > ---
> >     >   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;
> >
> >     dyn_csr_base_reg  seems have no additional effect on the function.
> >
> >     And It remains unmodified in following
> >     riscv_refresh_dynamic_csr_xml().
> >
> >     Regards,
> >
> >     Weiwei Li
> >
> >     >       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);
> >     > +}
> >
>
>

Weiwei Li May 24, 2023, 6:18 a.m. UTC | #5

On 2023/5/24 13:35, Tommy Wu wrote:
>
> Hi WeiWei Li,
>
> When the CPU is realizing, it will call `riscv_gen_dynamic_csr_xml` 
> for the first time with the correct `base_reg` value.
>
>
> code flow :
>
> riscv_cpu_realize
>
> → riscv_cpu_register_gdb_regs_for_features
>
>      → riscv_gen_dynamic_csr_xml
>
>
> The functionality of `cpu->dyn_csr_base_reg` is to record the 
> `base_reg` from
>
> `riscv_cpu_register_gdb_regs_for_features`.
>
>
> When we try to refresh the dynamic CSRs xml, we will call the function 
> `riscv_gen_dynamic_csr_xml`
>
> for the second time, and then we can give the correct `base_reg` value 
> to the function
>
> `riscv_gen_dynamic_csr_xml`, because we've record this value in the 
> `cpu->dyn_csr_base_reg`.
>
Oh. Sorry, I stuck.

Reviewed-by: Weiwei Li <[e-mail]>

Weiwei Li

>
> Best Regards,
>
> Tommy
>
>
>
> On Wed, May 24, 2023 at 10:10 AM Weiwei Li <[e-mail]> wrote:
>
>
>     On 2023/5/24 09:59, Tommy Wu wrote:
>     > Hi Weiwei Li,
>     >
>     > `dyn_csr_base_reg` will be used in `riscv_refresh_dynamic_csr_xml`
>     > We can initialize this variable when the cpu is realized.
>     I didn't find this initialization in following code.
>     > And used this variable in `riscv_refresh_dynamic_csr_xml`.
>
>     That's my question. In riscv_refresh_dynamic_csr_xml() ,
>     cpu->dyn_csr_base_reg is passed to riscv_gen_dynamic_csr_xml() as
>     base_reg.
>
>     And then base_reg is assigned to cpu->dyn_csr_base_reg again in
>     it. So
>     it's unchanged in this progress.
>
>     Another question is  dyn_csr_base_reg seems have no additional
>     function
>     currently.
>
>     Regards,
>
>     Weiwei Li
>
>     >
>     > Best regards,
>     > Tommy
>     >
>     >
>     > On Tue, May 23, 2023 at 10:38 PM Weiwei Li
>     <[e-mail]> wrote:
>     >
>     >
>     >     On 2023/5/23 19:44, Tommy Wu 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 <[e-mail]>
>     >     > Reviewed-by: Frank Chang <[e-mail]>
>     >     > ---
>     >     >   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;
>     >
>     >     dyn_csr_base_reg  seems have no additional effect on the
>     function.
>     >
>     >     And It remains unmodified in following
>     >     riscv_refresh_dynamic_csr_xml().
>     >
>     >     Regards,
>     >
>     >     Weiwei Li
>     >
>     >     >       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);
>     >     > +}
>     >
>

Alistair Francis May 25, 2023, 2:33 a.m. UTC | #6

On Tue, May 23, 2023 at 9:46 PM Tommy Wu <[e-mail]> 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 <[e-mail]>
> Reviewed-by: Frank Chang <[e-mail]>
> ---
>  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
>
>

Tommy Wu June 9, 2023, 8:37 a.m. UTC | #7

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 <[e-mail]>
wrote:

> On Tue, May 23, 2023 at 9:46 PM Tommy Wu <[e-mail]> 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 <[e-mail]>
> > Reviewed-by: Frank Chang <[e-mail]>
> > ---
> >  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
> >
> >
>

Alistair Francis June 12, 2023, 2:52 a.m. UTC | #8

On Fri, Jun 9, 2023 at 6:37 PM Tommy Wu <[e-mail]> wrote:
>
> 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);
>     ...
> ``` ?

Yeah, pretty much. We already have cpu-> gdb_num_regs we should be
able to use it directly.

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

That also works!

Alistair

>
> Best Regards,
> Tommy
>
> On Thu, May 25, 2023 at 10:33 AM Alistair Francis <[e-mail]> wrote:
>>
>> On Tue, May 23, 2023 at 9:46 PM Tommy Wu <[e-mail]> 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 <[e-mail]>
>> > Reviewed-by: Frank Chang <[e-mail]>
>> > ---
>> >  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
>> >
>> >

Patch

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);
+}